SERIAL NUMBER: K38-144C131-8LIR. s/n 8047

Transcription

1 OWNER S MANUAL MODEL: SERIAL NUMBER: K38-144C131-8LIR s/n 8047 i

2 Thank you for choosing SierraTherm as your controlled atmosphere conveyor furnace supplier. SierraTherm Production Furnaces, Inc. prides itself on the vast and diverse thermal processing experience that we have been able to apply to this product line. We have combined our experience together with the most advanced manufacturing operations and latest materials technology to produce superior thermal processing equipment. SierraTherm is dedicated to a high level of customer service in every aspect of conveyor furnace manufacturing, from design to production to field service. This manual is designed to provide detailed information on how to operate, troubleshoot and maintain your conveyor belt furnace. In addition to the hard copy of the Furnace Monitoring System (FMS) On-Line Help manual found at the end of this binder, the FMS portion of the manual can be accessed from the computer supplied with the furnace. Contact SierraTherm for further assistance with the operation and maintenance of your furnace or if you have any comments on the content of this manual. Our primary concern is satisfying the needs of our customers and your feedback is of great value to us. Contacting the Factory: SierraTherm Production Furnaces, Inc 200 Westridge Drive Watsonville, CA Tel: (831) Fax: (831) sales@sierratherm.com support@sierratherm.com Website: Safety Precautions Maintenance and service of SierraTherm equipment should be performed only by qualified personnel. Hazardous voltages, moving parts, compressed gases and high temperature surfaces may be encountered when panels are removed. ii s/n 8047

3 Table of Contents 1 OVERVIEW 1.1 System Description Atmosphere System Exhaust System Heated Chamber Cooling System Drive System Electrical System Overtemperature Protection System Entry and Exit Muffles EPO Switch System Optional Equipment Installed Element Continuity System SPECIFICATIONS 3 INSTALLATION 3.1 Unpacking and Inspection Inspection of the Furnace Checking the Packing List Furnace Installation Location System Maneuvering Assembly Leveling Utility Connections OPERATION 4.1 Initial Startup Procedures Typical Operating Procedures Shutdown Procedures Subsystem Operating Procedures TROUBLESHOOTING s/n 8047 iii

4 6 MAINTENANCE 6.1 Safety Precautions Periodic Maintenance Schedule Maintenance Procedures Cleaning Verification of Alarms Calibration Drive System General Maintenance Heating Elements Ultrasonic Belt Cleaner Brush Belt Cleaner Oxygen Analyzer & Sample System Furnace Temperature Profiling Furnace Data Log Assessment Repair & Replacement Thermocouples Heating Elements REFERENCE DRAWINGS 8 SUPPLEMENTARY MANUALS 9 RECOMMENDED SPARE PARTS LIST 10 WARRANTY 11 REFERENCE DATA iv s/n 8047

5 1 OVERVIEW 1.1 System Description The SierraTherm 7K38-144C131-8LIR controlled atmosphere conveyor furnace is designed for the primary purpose of firing thick film materials on silicon wafers in the 800 to 900 C range in an air atmosphere. The following sections describe the function of the various systems composing the furnace Atmosphere System Clean, dry, compressed air is input to the furnace at the utility fitting bracket located on the back side near the exit end of the furnace. The main air supply line is connected to a flow meter manifold located on the control panel at the front side entry end of the furnace. The flow meters provide gas for the entry curtain, dryer atmosphere, firing atmosphere, cooling quench, and exit curtain. Each of the flow meters are separately adjustable to provide the required amount of gas flow to each independent location. Refer to the atmosphere plumbing schematic in the Reference Drawings section for atmosphere system details Exhaust System An extractor designed to remove burnout materials from the furnace process chamber is located between top elements in the burnout region. The exhaust assembly utilizes an air powered venturi exhaust blower which operates using compressed air from the main supply line. The exhaust flow is controlled by adjusting a pressure regulator located on the control panel. The exhaust flow velocity is then monitored by a magnehelic gauge, also located on the control panel, which measures the pressure difference between the inside of the exhaust tube and the room. The magnehelic pressure gauge reads out in inches or millimeters of water column Heated Chamber The furnace heating system consists of multiple electrically powered, independently controlled heating zones. Layers of low mass ceramic and mineral fiber insulation minimize heat loss while maximizing responsiveness to changes in temperature setpoints. Each heating zone is monitored and controlled by the SierraTherm Furnace Monitoring System. The heating elements consist of tungsten filament, clear quartz IR lamps located above and below the conveyor belt. Top to bottom trim is provided through the temperature controller. The trim function is intended to compensate for minor differences in top to bottom heating rate. The top and bottom should be set to similar trim values if possible so that all of the lamps are providing power to the zone. If it becomes necessary to set the trim out of balance (99/60 for example), please contact the factory Cooling System A water cooling system is provided to help cool the belt and parts as they exit the heated section as well as to dissipate heat generated from the solid state relays. The water supply and return are plumbed to the furnace at the utility input bracket. The water flows through the solid state relay aluminum extrusion then through the aluminum extrusions on the cooling muffle, through a water flow switch and out the bulkhead fitting on the utility bracket. The recommended water flow rate is described on the Outline and Utility Connections Drawing in the Reference Drawings section of this manual. In order to keep the cooling section and drive system from being damaged, a water flow switch will disable conveyor and element power and activate an alarm if the flow rate drops below a pre-set level. The exit water temperature is monitored with a thermocouple mounted in the exit water plumbing line and displayed on the FMS computer. s/n

6 The cooling system is equipped with a drain valve located near the solid state relay panel. A bypass valve in the same area allows flow through the solid state relay heat sink to be reduced in the event condensation occurs on the heat sink. In addition, an array of nozzles in the top of the water cooling section sprays air on the wafers as they exit the heated section. Flow to the nozzles is controlled by the Firing Section Atmosphere flowmeters. After the wafers exit the water cooling section they pass through a short transition area where there is natural convection cooling only. A forced air cooling system is provided after the transition section to help further cool the belt and wafers. An array of fans located above the cooling hearth forces air down through the belt. Power to the cooling fans is switched by the Cooling Fan Power switch on the control panel. The cooling fans are arranged in trays that are removable in order to simplify fan replacement Drive System The drive system is located at the exit end of the furnace below the cooling muffle. A single snubbed friction pulley drive is used to pull the conveyor belt through the system. The drive pulley is rubber coated (lagged) to provide traction against the belt. An adjustable snub roller is used to increase the angle of belt wrap around the drive pulley. In addition, the snub pulley also functions as a pinch pulley to further increase traction between the belt and the lagged drive pulley. The drive pulley is driven by a DC electric motor via a worm gear speed reducer and a roller chain drive. A torque limiter is mounted on the main drive sprocket to protect against overload conditions. The breakaway torque provided by the clutch is adjustable and should be set under normal process conditions. The breakaway torque value set at the factory is an estimated value only. Refer to the Supplementary Manuals section for adjustment instructions Electrical System Power to the furnace is provided to the contactor enclosure located at the exit end, rear side of the furnace next to the utility manifold. Refer to the Electrical Schematics in the Reference Drawings section for the voltage and load specifications. The main supply cables are connected to the top of the element contactor. Power is then routed to the heating elements. Power to the control system is provided through a 115 volt step down transformer that is located next to the contactor. The control power switch located on the control panel provides power to the rest of the control system. Power to the heating elements is provided through time proportioned solid state relays. A thermocouple mounted above the belt in each furnace zone provides the input signal to the furnace control system which compares the temperature setpoint with the actual temperature. A 5 VDC signal from the ssr interface card then controls the solid state relays and consequently the power to the heating elements. Refer to the FMS on-line manual for a more detailed description of the electrical system. Warning: The electrical connection of this system to the facility power supply should be performed only by a qualified electrician Overtemperature Protection System Redundant over temperature protection is provided in all furnace zones through an independent over temperature controller sensing unit and a thermocouple located in each zone. The over temperature controller is pre-set at the factory to prevent a condition which could cause damage to the furnace. In the event of an over temperature condition the element contactor is opened removing power to the heating elements. In addition visual and audible alarms are activated. After the fault causing the over temperature condition has been corrected, the over temperature reset button located on the control panel should be depressed to reestablish element power. 1-2 s/n 8047

7 1.1.8 Entry and Exit Muffles The entry and exit muffles are constructed of 304 stainless steel. The entry muffle is a rectangular tube structure with perforated entry curtain and burnout atmosphere plenums. Gas to each plenum is supplied through a 1/2 (13 mm) stainless steel inlet tube that ensures uniform distribution across the belt. The cooling muffle is similar in construction to the entry muffle, except that the plenums in the cooling muffle are for the firing atmosphere and exit curtain. Both muffles are designed with removable baffle door assemblies to isolate the furnace process atmosphere from the room atmosphere EPO Switch System Emergency Power Off switches are located at each end of the furnace. These switches are wired in series on a 24 volt normally closed circuit. Pressing any of the EPO switches (or a break in any of the wiring in the circuit) will immediately cut off power to the machine. The only wiring that will be hot after pressing an EPO switch is to the 24V power supply in the contactor enclosure. When the furnace has been shut down by an EPO switch, the following procedure should be used to power up the machine: Determine the cause for the switch being pressed, and be sure that any hazardous condition has been corrected. Twist the switch that was pressed in order to close the switch contacts. Press the control power switch. Resume furnace operation. 1.2 Optional Equipment Installed Element Continuity System Power to the heating elements is monitored with a current transformer. If no current is detected when the solid state relay is closed, an open element alarm will be activated. This system will also activate an alarm in the event that a solid state relay fails in a closed (shorted) condition. s/n

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9 2 SPECIFICATIONS Remove this page and replace with the furnace procurement specification. s/n

10 SIERRATHERM PRODUCTION FURNACES, INC. 200 Westridge Drive Watsonville, CA PROCUREMENT SPECIFICATION SierraTherm SERIES 7500 MODEL 7K38-144C131-8LIR INFRARED THICK FILM DRYING/FIRING FURNACE

11 Procurement Specification August 2005 SierraTherm 7500 Series Model 7K38-144C131-8LIR Thick Film Drying/Firing Furnace 1. General Description This specification describes a multiple zone, electrically heated, conveyor furnace capable of operating to 1,000 degrees centigrade. The furnace includes a controlled air atmosphere system for the primary application of drying and firing thick film materials on solar cells. 2. General Specification Overview Inch A. Belt Width: 38 B. Heated Length: 144 C. Product Clearance Above Belt: 0.5 D. Dimensions: Entry/Exit Tables: 24 Overall Length: 352 Height: 50 Width: 70 Conveyor Height: 36 Leveling Range: ±1 F. Belt Speed Range: Minimum Maximum 17/min 170/min G. Number of Heated Zones: 8 H. Atmosphere: Air I. Input Power: 480 VAC 3 Phase, 3 Wire 60 Hz 255 KVA Max J. Approximate Weight: 7,300 lb. Page 2

12 Procurement Specification August 2005 SierraTherm 7500 Series Model 7K38-144C131-8LIR Thick Film Drying/Firing Furnace 3. Heated Section A. Nominal Operating Temperature: Ambient to 600 degrees centigrade in the dryer section and 1000 degrees centigrade in the firing section. B. Heating Method: Fast response heating section with Type T-3 tubular quartz tube I-R lamps located above and below the conveyor belt. Quartz inserts shall be installed on side insulation for IR Lamp support. C. Insulation: Multi-Layered, thermally optimized, graded, insulation provides efficient thermal stability, cool external panel surfaces and minimal heat loss. Low mass refractory materials are utilized throughout the heated chamber resulting in rapid heat-up and cool-down times. High temperature glazing is applied to all interior chamber surfaces to ensure a clean, stable, processing environment. 4. System Layout Inch A. Entrance, including atmosphere 18 inlet, air curtain and baffle door assembly KVA B. Zone Zone Zone Zone C. Transition with atmosphere exhaust 6 D. Zone Zone Zone Zone Note: Shadow walls formed with ½-inch thick ceramic fiber-board are positioned between each zone for isolation and provides 1/2-inch clearance above the belt. E. Insulated Exit 6 F. Water Cooled Section with air 48 inlet and exit air curtain G. Free Cooling 12 H. Fan Cooling Section 70 Page 3

13 Procurement Specification August 2005 SierraTherm 7500 Series Model 7K38-144C131-8LIR Thick Film Drying/Firing Furnace 5. Loading/Unloading Tables Inch A. Loading Table B. Unloading Table Width: 70 Length: 24 Width: 70 Length: Conveyor System A. Belt Type: Nichrome V, 38 inch wide B. Belt Mesh: C. Belt Loading: 0.5 pound per square foot D. Belt Speed: inches/min E. Speed Control: Microprocessor controlled, closed loop, digital feedback, ± 0.1% accuracy F. The belt shall ride on quarts tubes or other suitable iron free materials throughout the entire path. Note: The belt speed range specified above refers to adjustability of belt speed only and does not imply compliance with load and temperature requirements over the entire range of belt speed adjustability. 7. Temperature Control System The furnace is controlled with a MicroTherm temperature control system. The MicroTherm is a high performance, single board computer with full PID control for up to 16 furnace channels. Each furnace zone is monitored and controlled with a type 'N' thermocouple positioned in the center of each heated zone. Separate power trim controls shall be provided for power adjustment to top and bottom lamps in zones 5-8. The MicroTherm incorporates closed loop conveyor speed control accurate to + 0.1%. (See separate MicroTherm specification for a comprehensive list of temperature control system features.) 8. User Interface System A Pentium based PC with a Flat Panel Monitor is provided for user interface. The User Interface Computer communicates with the Temperature Controller on a high speed serial link. A complete description of the User Interface features is described in a separate specification. Page 4

14 Procurement Specification August 2005 SierraTherm 7500 Series Model 7K38-144C131-8LIR Thick Film Drying/Firing Furnace 9. Overtemperature Safety Protection The furnace is supplied with a second set of thermocouples and overtemperature safety protection system that will open the element power contactor in the event of an overtemperature condition. 10. Atmosphere Control System A. The following flow meters supply air to the process chamber: SCFH 1. Entry Curtain Dryer Atmosphere Inlet Firing Atmosphere Inlet Exit Curtain Atmosphere Exhaust The furnace is supplied with a variable flow, exhaust extractor located in the transition section between the dryer and the firing section. The venturi exhausters are provided with a removable condensate collection trap, flow controls and monitors. The process cooling atmosphere shall be exhausted downwards through the belt and guided to an exhaust duct. 12. Operating Instruction Manuals The furnace is supplied with two copies of instruction manuals covering all phases of installation, operation, and maintenance procedures. 13. Code Compliance SierraTherm production equipment is manufactured in compliance with the National Electric Code (NEC). Any requirements for compliance with local codes or customer specifications must be supplied to SierraTherm and agreed to by SierraTherm prior to order acceptance. Costs for third party inspections or certifications of the equipment shall be the responsibility of the customer unless specifically stated. Page 5

15 3 INSTALLATION 3.1 Unpacking and Inspection Inspection of the Furnace Inspect the furnace for damage or signs of rough handling which may have occurred during shipment. If you detect any signs of damage, notify the shipping carrier and SierraTherm at once Checking the Packing List The packing list for your system is located on the end of the frame (or the end of the crate if the machine was crated). Check it against the contents of the boxes that were shipped with the furnace to make sure that you received everything on the list. The boxed items would typically include the computer, monitor, keyboard tray, profiling thermocouples (if ordered) and any spare parts that were ordered with the system. 3.2 Furnace Installation Location The first step in the installation of your conveyor furnace is to identify a suitable location. The location should allow a minimum of three feet on both sides of the furnace to permit access to the panels for maintenance and trouble-shooting. Clearance on both ends of the furnace should permit loading of parts and allow access to both sides of the unit by operators and maintenance personnel. The system should be located in an area that is free of room drafts and away from frequently used doorways, open windows, ventilation ducts, fans or any other areas where random air flows might affect furnace chamber conditions. The floor must be capable of supporting the weight of the unit as described in the furnace specification and distributed on the leveling pads as illustrated in the furnace outline and utility drawing (see Reference Drawing section) System Maneuvering Standard rigging equipment (jacks, dollies, J-bars, etc.) can be used to move the system into place. Rough handling and excessive tipping should be avoided to prevent damage and/or shifting of insulation, elements or muffles. The system should never be dropped, even a very small amount, as this can damage the insulation and elements. The system should be lowered onto blocks approximately 2 cm thick. The leveling legs can then be used to lift the system off the blocks Assembly Frame and Muffle If the main frame was built in multiple sections and split apart for shipment, the following steps are necessary: 1. Place the heated section frame in the desired location. 2. Move the cooling section frame to within approximately 300 mm of the heated section frame. 3. If the conveyor belt is inside the cooling section, then connect the belt to the heated section belt with the connector wire provided. If the belt is rolled up at the unload end of the machine, then feed a pull wire through the cooling section. Use this wire to pull the conveyor belt through the cooling section. s/n

16 4. For a muffle furnace, locate the muffle flange angles, bolts, and flange gasket. A 1500 series furnace (no muffle) does not have a gasket, bolts or angles. The cooling section extends inside the heated section approximately two inches. Strips of ceramic fiber blanket insulation make the seal between the cooling section and the heated section. 5. Move the cooling section portion of the frame into position against the heated section frame. Use the leveling legs to line up the two sections. 6. Install the muffle flange gasket between the flanges and hold in place by inserting bolts through the top two corner holes. Nuts should not be tightened at this time. Use the angles to back up both sides of the flanged connection. 7. Bolt the frame sections together first and then make the muffle flange connections. A small amount of anti-seize compound on the muffle flange bolts will help if the flange needs to be disassembled in the future. 8. Make all electrical and plumbing interconnections Tables If the tables were removed for shipment, the following steps are necessary: 1. Remove the entry and exit tables from the crate and locate them at the respective ends of the furnace. 2. The load and unload tables can be identified by the description on the top of the tables. 3. Remove the ties that hold the conveyor belt in place for shipment. 4. Move the conveyor belt away from the entry and exit ends of the furnace to make room for mounting the tables. 5. Install the table sections by threading the four bolts provided through the slots in the table angles and then through the slots in the frame angles. The washers should be mounted with one on the inside of the table angle and one washer and lock-washer on the inside of the frame angle. 6. Screw on the nuts finger tight. 7. Adjust the two table height adjusting bolts until the tops of the belt support angles are approximately 0.5 to 1.0 mm above the entry muffle for the load table and 0.5 to 1.0 mm below the cooling muffle for the unload table. 8. Make sure the table is level and square with the frame and tighten the bolts Belt 1. Locate the belt slack at the entry end of the furnace behind the panels and remove the shipping ties. 2. Thread the belt over the return track in the entry table, around the end pulley and onto the top of the table. 3. Bring the two ends of the belt together on the top of the entry table and attach them using one of the belt cross link wires taped to the table top. It is not necessary to weld the cross wire to the spirals. Note that there are left and right hand spirals that should be alternated as the belt is reassembled. 4. Repeat the steps above for the belt located at the exit end of the furnace. 5. Inspect the conveyor belt throughout the furnace to ensure the belt is located between all sets of guide bearings Computer 1. Remove the computer, monitor, keyboard, mouse and cables from the shipping boxes. 3-2 s/n 8047

17 2. Put the computer into the sheetmetal computer box. Put the monitor on the platform on top of the frame. Hang the keyboard tray on the side panel below the monitor platform. Set the keyboard and mouse on the keyboard tray. 3. Connect the cables to the computer following the labels on the computer and cables Heating Elements (Infrared lamp type furnaces only) Tungsten filament quartz lamps (Infrared type furnaces) are removed from the machine for shipment in some cases. They will need to be re-installed and electrically connected before the furnace can be operated. The lamps are very fragile, and should be handled with great care. Clean cotton gloves should be worn when handling quartz elements. Never touch elements with bare hands because oils and contaminants from the skin could be deposited upon the quartz sheath and would cause hot spots and possibly premature lamp failure. If the quartz is contaminated, use a clean cloth with water or alcohol to clean. Lamp installation should be performed by two people. Straighten the lead at one end of the lamp and guide the lead through the hole in the insulation. As the lamp itself begins to pass through the insulation, be sure that the tab at the end of the lamp is aligned with the slot cut in the insulation. A second person should be positioned on the far side of the insulation to catch the lead and gently guide the lamp through the insulation. An alternate method would be to insert a small diameter stainless tube (similar to the diameter of the lamp) through the insulation package first. The lamp lead could then be inserted into one end of the tube, and the tube pulled through from one side as the lamp is pushed in from the other. Center the lamp in the insulation package and connect the leads to the terminal blocks that are located on the frame. The leads are used to keep the lamp centered in the furnace, so they should be snug, but not pulled so tight that the lamp is damaged. Re-install any safety covers that were removed during lamp installation Leveling Once the unit has been placed in the desired location the furnace should be properly leveled and the conveyor belt height adjusted. Leveling the furnace helps ensure that the belt is tracking properly and that heat is distributed uniformly throughout the process chamber. The machine is leveled by adjusting the nuts on the leveling pads which are pre-assembled in the bottom of the furnace frame. The leveling pads should be adjusted until all sides of the furnace are level Utility Connections Electrical Route the electrical supply cables to the system in a conduit from a fused disconnect switch if one was not supplied with the system. The switch should be properly sized and located in accordance with local electrical codes. Refer to the Electrical Schematic in the Supplementary Manuals section for the voltage and load specifications in order to correctly size the cables and conduit. Connect the conduit to the top of the contactor enclosure (refer to the Outline and Utility Input Drawing in the Reference Drawings section for the location). Connect the cables to the lugs on the top of the contactor. Connect the ground wire to the lug provided inside the enclosure. Note: If an optional disconnect switch is provided on the system, connect the cables to the lugs at the top of the switch. The bottom of the switch is connected to the contactor at the factory. Warning: All system circuit breakers should be turned off until after primary power is applied and voltages to each circuit are verified. See section 4.1 for the initial startup procedure. The procedures described in this section should be performed only by a qualified electrician. s/n

18 Exhaust Plumb the facilities exhaust ducting to a hood located over each furnace exhaust duct. The hood should be mounted approximately 150 mm above the exhaust duct and should be at least 300 mm in diameter at the bottom. It is important that the facility exhaust ducts not be directly coupled to the furnace exhausts. Variations in facility exhaust pressure may cause fluctuations in chamber atmosphere if a direct connection is used Plumbing Connect each utility supply (or return) to the appropriately labeled bulkhead fitting. Refer to the Outline and Utility Connections drawing in the Reference Drawings section for the location of the utility inputs and recommended pressures and flows. Unless otherwise arranged, the main shutoff valves, pressure regulators, and filters for the utilities are not provided on the furnace. It is recommended that the appropriate valves, regulators, and filters be installed above the furnace frame in the utility input area. A flowmeter on the Water Out line is helpful to monitor water consumption. 3-4 s/n 8047

19 4 OPERATION 4.1 Initial Startup Procedures Once the furnace has been properly installed the following procedures should be performed during the initial start-up. The voltage check procedures should be performed only by a qualified electrician. If Sierratherm field service personnel are contracted to perform the start-up, they will perform the following checks. 1. Turn off all circuit breakers and remove all fuses on the furnace. There are circuit breakers in the contactor enclosure for the various control circuits, and circuit breakers or fuses in the SSR/control system enclosure for the heating elements. Refer to the electrical schematic in the Reference Drawings section for the voltage verification steps that follow. 2. Unplug the connectors that supply power to the overtemp card, the SSR interface card, and control computer card. 3. Check to see that all of the switches on the control panel are in the off position. 4. Turn on the disconnect switch. 5. At the top of the contactor (usually labeled 1CON), measure the voltage between the two phases that power the control circuits. This voltage should fall between 208 and 480 volts. This is the range for which the control transformer can provide 115 volts to the control system. If the voltage measured is outside of this range, contact SierraTherm. If the voltage is within this range, check the diagram on the top of the control transformer to verify that the taps are set to provide 115 volts on the output. 6. Once the taps are set correctly, then turn on the circuit breaker that powers the control transformer. This transformer powers the control system and computer, and is typically labeled 1T. Measure the output voltage. It should fall between 110 and 125 volts. If it does not, then turn the circuit breaker off and adjust the transformer taps as needed. 7. Turn on the circuit breaker that powers the isolation transformer. This transformer provides isolated power to the computer and power supply for the control electronics. It is typically labeled 2T. Measure the output voltage at the circuit breaker on the output side of the transformer. If the voltage is in the 110 to 125 range, then turn on the output side circuit breaker to power the computer receptacle. If the voltage is not in the 110 to 125 range, then turn off the circuit breaker that powers the isolation transformer and re-check the control transformer output voltage. 8. Turn on control power and check the power supply output voltages (+12VDC, -12VDC, and +5VDC). The 12V supplies should be between and volts, and the 5V supply should be between 5.05 and 5.08 volts. If these voltages are correct, then turn off control power and plug in the overtemp card, the SSR interface card, and the control computer (TCS) card. 9. Turn on control power and check to see that the 5V supply is still between 5.05 and 5.08 volts. 10. Turn on computer and monitor power. The computer will boot up to the Furnace Monitoring System and display the temperature settings and other control parameters that were saved from the last time the furnace was used. Control power must be on before FMS is started, otherwise the initial communication between the controller and the FMS software will be incomplete. 11. Ensure that the computer screen saver is turned off and that none of the power saving options are being used. Some of these options may cause communication between the furnace and the computer to stop. 12. Program all furnace zones to 0% power. 13. Open valves on cooling water supply and return. The water flow switch will disable the heating elements if the water is off. 14. Turn on element power. s/n

20 15. Check the voltage to the heating element system at the 3-pole distribution block on the SSR panel. This voltage should be between 208 and 240 volts. This is the range that the heating element coils are designed for. 16. Program the furnace zones to the desired temperatures. The maximum temperature setting for furnace zone one is 600 C, all other zones have a maximum temperature rating of 1000 C. Refer to the FMS On-line Help manual on the computer or the hard copy located in the Supplementary Manuals section of this manual for programming details. 17. Set the rise rate in all furnace zones to 5 degrees per minute. The furnace temperature should be brought up slowly to check the operation of each furnace zone. The rise rate can be increased to 20 degrees per minute after the initial startup. 18. Set the maximum power in zone one to 50%. Turn on the circuit breaker for zone one (if fuses are used, turn off element power and plug in the fuse). Check the current to the zone one heating elements using a clamp-on ammeter. If the current is as expected (per the electrical schematic), then reset the maximum power to 0%. Repeat the procedure for each zone. 19. Check the function of the thermocouple input card by unplugging the control thermocouples one zone at a time (refer to the electrical schematics for wire numbers). The computer should show an open thermocouple as reading full upscale (around 1200 degrees). This will turn off power to the zone affected and cause the alarm to activate. 20. Check the function of the overtemp card by unplugging the overtemp thermocouples one at a time. The overtemp card should activate the alarm and turn off power to all elements (you will hear the contactor switch to the open position). Look on the overtemp card to see that the LED that is lit corresponds to the zone that is unplugged. Plug the thermocouple back in and press the Overtemp Reset button. Repeat the procedure for each zone. 21. Once all zones have been checked, set the maximum power to 50% in all zones and allow the furnace to begin heating up. The maximum power should be raised as needed to reach setpoint. Check to make sure each zone is coming up to the set point temperature and staying within the limiting parameters. 22. The control parameters (PID settings) should be as follows initially: Proportional Band - 30 Degrees, Integral (Reset) repeats per minute, Derivative (Rate) - 0 minutes. 23. Set the belt speed to 2 inches per minute and turn on Conveyor Power. The belt should be run slowly at first to check the belt tracking system, to ensure that the belt is traveling freely, and to ensure that the torque limiter is not slipping. Refer to the torque limiter data sheet in the Supplementary Manuals section for instructions on how to set the clutch tension. 24. Open the valve on the main air supply and set the pressure to 70 psi (480 kpa). 25. Adjust the entry curtain flowmeter to approximately 200 cfh (95 lpm). 26. Adjust the dryer atmosphere flowmeters to approximately 150 cfh (70 lpm) each. 27. Adjust the firing atmosphere flowmeter to approximately 150 cfh (70 lpm) each. 28. Adjust the cooling quench flowmeters to approximately 200 cfh (95 lpm) each. 29. Adjust the exit curtain flowmeter to approximately 100 cfh (50 lpm). 30. Adjust the exhaust pressure to approximately 0.05 inches of water (1.3 mm of water). Note that the flowmeter and exhaust settings described here are preliminary and not necessarily the final settings for your process. 31. Once the furnace has reached the desired set points allow the furnace to stabilize for 8 hours. Periodically check the temperature control and belt tracking systems to ensure they are operating properly. 32. After the furnace has run for 8 hours the belt speed and rise rate parameters can be adjusted as required. 4-2 s/n 8047

21 33. Follow the shutdown procedures in section 4.3 when turning the furnace off. 4.2 Typical Operating Procedures After the furnace has been brought up to typical operating conditions during the initial start-up procedures and thoroughly checked out, typical operating procedures should be performed as follows: 1. Open main air supply valve and set the pressure to 70 psi (480 kpa). 2. Open cooling water supply and return valves. Set the cooling water flow rate to 180 gallons per hour (12 lpm). 3. Turn on control power. Control power must be on before the FMS software is started. 4. Turn on computer and monitor power. The computer will boot up to the Furnace Monitoring System and display the temperature settings and other control parameters that were saved from the last time the furnace was used. 5. Load the required recipe from the recipe menu or input new operating parameters to accomplish a specific profile (refer to the on line FMS manual for details on setting operating parameters). 6. Adjust the flowmeters and exhaust pressure as needed. 7. Turn on conveyor power. 8. Turn on element power. 9. Once the furnace has reached the setpoint temperatures and is stable, parts can be loaded onto the belt. Once the belt is fully loaded, check the adjustment of the torque limiter to be sure that the setting is appropriate for your process conditions. 4.3 Shutdown Procedures 1. Turn off element power. Allow the furnace to cool down to 400 C before turning conveyor power off. 2. Turn off conveyor power 3. Save any recipes, profiles or other furnace parameters as required. 4. Exit the Furnace Monitoring System. 5. Exit the Windows operating system. 6. Turn off computer and monitor power. 7. Turn off control power. 8. Close all flowmeter valves. 9. Turn off exhaust pressure regulator. 10. Close valve on main air supply. 11. Close valves on cooling water supply and return. 12. Turn off main power to the furnace at disconnect 4.4 Subsystem Operating Procedures This section is intended to contain answers to some frequently asked questions, and provide some practical tips for operation of the following systems. Your furnace may not include all of the systems mentioned in this section. Contact SierraTherm if further information is needed. s/n

22 4.4.1 Temperature Profiling Since the furnace control thermocouples are measuring temperature near the heating elements or on the muffle, they are not a true indication of the temperature of the parts being processed. Periodic temperature profiling using one or more traveling thermocouples is the typical method for verifying the actual part temperatures. These thermocouples are connected to the furnace control system and temperatures are recorded using the temperature profiler feature in the FMS software. The following items are important to consider when running a temperature profile: 1. A typical traveling thermocouple will last only about 10 to 15 cycles through a high temperature furnace (850C). Lower temperatures and extra care in handling the thermocouple can extend the life, but a profiling thermocouple should be considered a consumable item. 2. If a multiple point temperature profile is desired, such as in furnaces that have side to center heating element trim, it should be noted that thermocouples can vary in temperature measured by several degrees. If an accurate side to side or side-center-side profile is needed, select thermocouples from the same lot number of wire if possible, and run all of them through the furnace together to see if there is a difference in temperature measured. Record the difference at the peak temperature and use this difference to normalize future profiles. The SierraTherm profiler has a TC Calibration Offset feature that can be used to adjust a profile up or down. A positive number entered into the Calibration Offset box will raise the profile, and a negative number will lower the profile. 3. The single most important thing to remember about profiling is consistency. Inconsistent methods can cause significant changes in the measured profiles. Pay particular attention to the following: It is crucial that the tip of a sheathed thermocouple or the thermocouple junction on an exposed thermocouple (where the two wires are welded together) is in firm contact with the part being profiled. If the thermocouple is not in contact, the atmosphere around the junction will heavily influence the measured temperature, resulting in an inaccurate profile. Cover the junction to minimize atmosphere effects. This will give a more accurate representation of the part temperature. The junction can be covered by placing a thin ceramic substrate over it or by attaching the junction to the part with a small amount of ceramic adhesive. Use the same substrate each time. Substrates of different size, mass, specific heat, or color will profile differently. On a multiple point profile, place the thermocouples the same distance in from the edge each time. Be sure that the thermocouple junctions are in a straight line across the belt so that they all enter the furnace at the same time. 4. The traveling thermocouple should be tied to the belt mesh with fine gauge (approx 24 gauge) chromel, nichrome, or other suitable high temperature wire. Attach the thermocouple to the belt in two or three locations to minimize the possibility of the junction shifting on the part as the conveyor pulls the thermocouple through the furnace. 5. It is possible on a non-muffle furnace for the profiling thermocouple to touch the top heating elements. When a profile is complete, use caution and pull the traveling thermocouples back slowly or turn off the element power while the thermocouples are being removed. 6. Use only ungrounded thermocouples when profiling. The profiling thermocouples share the same circuitry as the furnace control thermocouples. The thermocouple input circuit is floating, meaning that there is no connection to earth ground or circuit common. This is important for noise immunity. A path to ground (such as with a grounded junction thermocouple) can allow AC noise to affect the profile. A profile that is affected by noise will not appear smooth; the trace will jump up and down very quickly, especially at higher temperatures. The profile thermocouple will be grounded if the junction is allowed to touch the belt mesh. A ceramic substrate between the junction and the belt will prevent the junction from grounding. If noise is still present on a profile, a trick that sometimes helps is to use a short length of copper wire to ground the thermocouple sheath to the furnace frame. 4-4 s/n 8047

23 7. A relatively new thermocouple, type N, has proven to be superior to type K for profiling at high temperature. Repeated cycling above 550 C degrades type K thermocouples faster than type N. SierraTherm has begun shipping new furnaces with type N profiling thermocouple jacks. Furnaces with type K jacks can easily be converted to type N. Contact SierraTherm for details Power Trim Adjustment On furnaces with power trim capability, the power to the left, center, and right heating coils can be adjusted separately to help minimize cross belt temperature gradients. The information gathered by profiling is used to decide which power levels to adjust. The maximum power feature is used to proportion the power levels. If, for example, the center is set to 70% max power and the sides are set to 90%, the center will always operate at 7/9 of the power that the sides operate at. If the production load warrants 45% power at the sides, then the center will operate at 7/9 of 45, or 35%. A good starting point for trim ratio is left=1.0, center=0.75, and right=0.90. If the left side is set to 75%, this will result in the center being 56% and the right being 68%. This will not work in all cases, but it should be a good starting point. The zone control thermocouple position should be noted when making trim adjustments, especially when profiling. The control system will try to maintain the setpoint at the control thermocouple. Typically (but not always) the control thermocouple is in the center on a non muffle furnace, and on the left for a muffle furnace Oxygen Analyzer & Sample System Refer to the sample system plumbing schematic in the Reference Drawings section when reading the following instructions for the analyzer and sample system. 1. Don t operate a Delta-F oxygen analyzer for more than a few seconds while exposed to air. This analyzer typically takes an hour or more to achieve a stable reading anytime the electrolyte has been exposed to air. Be patient when waiting for a reading! 2. Always establish sample flow before powering up the analyzer. 3. Never operate the analyzer for more than a few minutes without sample flow. 4. If there is a chance that there is air trapped in a sample line, purge the line in order to avoid drawing the air into the oxygen analyzer. This is accomplished by opening both the N2 supply selector valve and the valve to the sample port of interest. This will cause pressurized nitrogen to be forced into the sample line, which will push any air into the muffle where it will be diluted. When completed (10 to 20 seconds should be enough), the N2 Supply valve can be shut off and the oxygen analyzer sample pump turned on. 5. Bleed a small amount of the source nitrogen (approximately 0.5 lph) through the analyzer when it is not in use. This prevents air from getting into the sensor. The sample pump is not needed for this Ultrasonic Belt Cleaner Deionized water is recommended for use in ultrasonic belt cleaners. The cleaning efficiency is increased by using water that is free of minerals and other contaminants. Distilled water can be substituted if deionized water is not available. The use of city water is not recommended, as it may have a high mineral or chloride content. Minerals and chlorides in the water can decrease the efficiency of the cleaner, and they may be deposited in the cleaner and plumbing. Heavy mineral deposits can lead to failure of the level switch or other components. It is usually not necessary to run the ultrasonic belt cleaner continuously. Use the timer provided in the FMS software to run the belt cleaner for 1 or 2 revolutions of the belt once a week. Increase the frequency or duration of the cleaning as needed to keep the belt clean Facility Exhaust Connection It is recommended that the furnace process exhaust never be connected directly to the facility exhaust. An indirect connection is the preferred method, where a small hood is suspended above the furnace exhaust s/n

24 stack. If a direct connection is made, any fluctuations in facility exhaust pressure will cause conditions inside the furnace chamber to change. The indirect connection method ensures that changes in the furnace exhaust flow rate are done only by the furnace controls Exhaust/Atmosphere Balance It is often useful to balance input and exhaust flows in order to avoid burnout products escaping into the room or an excessive amount of room air being drawn into the furnace. The typical procedure for balancing a thick film firing furnace would be to start with all flowmeters and exhausters off. Open the burnout flowmeter(s) to the amount recommended by the paste supplier. (The V=PLAWS formula from DuPont is the most common method for calculating burnout flow.) Open the firing section flowmeters to 1.1 to 1.2 times the burnout flow. Turn on the exhauster(s) until room air is just being drawn into the furnace. A small amount of smoke at each end of the furnace can be used as a flow direction indicator. Smoke generators for this purpose can usually be found at an air conditioning equipment supply company. Dry ice vapor can be used in situations where smoke is undesirable (such as in a clean room). The last step is to turn up the entry and exit curtain flows until the flow at both ends is out of the furnace. This ensures that room air will not be drawn into the furnace. The furnace is usually equipped with a magnehelic or photohelic gauge for measuring exhaust pressure. This gauge is provided only as a relative measurement of exhaust flow so that there is a setting to return to once the process is satisfactory. The magnehelic gauge reading cannot be easily related to flow for comparison with flowmeter settings. Even if the exhaust pressure reading was converted to flow rate, it could not be compared directly to the flowmeter settings. The incoming flow is heated and expands by a significant amount, so the input and exhaust flows will be different. Also, flowmeter calibration pressure vs. actual pressure can cause error, and the fact that some of the curtain flows may escape into the room make it difficult to directly compare input flows to exhaust flow. 4-6 s/n 8047

25 5 TROUBLESHOOTING This section provides basic troubleshooting suggestions that can be used to diagnose and correct various system failures. The procedures outlined in this section cover a wide range of furnace model types. Some of the following may not apply to your furnace. Troubleshooting procedures can involve work with hazardous voltages, high temperatures, moving parts, and pressurized liquids and gases. The following procedures should be performed only by qualified personnel. Contact SierraTherm if you are uncertain about any of the following items. The specific topics covered in this section are as follows: Communication Problems Over Temperature Alarm Zone Won t Reach Setpoint Temperature Water Flow Alarm Belt Speed Problems Temperature Controller Problems Furnace Installation Problems System Controls Temperature Profiling Problems s/n