USER S GUIDE FOR CLEARWELD/EFD DISPENSING KITS

Transcription

1 USER S GUIDE FOR CLEARWELD/EFD DISPENSING KITS IMPORTANT! The instructions in this manual pertain specifically to the use of Clearweld coatings with EFD dispensing equipment. It is important that you refer to the EFD documentation included with the Kit and thoroughly familiarize yourself with the equipment and general operating procedures before you start dispensing.

2 TABLE OF CONTENTS Introduction... 4 Requirements for a Successful Clearweld Process... 5 Application Methods... 5 Dispense Valve/Valve Controller Kit V-SS-CW Dispense Valve... 7 ValveMate 7000 Valve Controller... 7 Dispense Valve/Automated XYZ Dispensing System Kit... 8 Fluid Reservoirs...9 Dispense Tip... 9 Setup Procedure Shutdown Procedure Dispense Tip Maintenance Troubleshooting Handling, Storage and Safety Considerations Packaging Handling and Storage Safety Information Contact Information

3 Introduction Clearweld coating systems permit laser welding of clear thermoplastic substrates. A thin layer of light-absorbing coating material is deposited onto the plastic surfaces. When light from an infrared laser is applied, this layer absorbs the energy and forms a weld by melting the plastic substrates. Since the absorbing materials used in Clearweld coatings are not soluble in water, a variety of common solvents are used to form solutions that can be applied to the surface of plastic parts. Typical solvents used include ethyl alcohol, acetone, and methyl ethyl ketone. The specific Clearweld solution selected is dependent on the plastic being coated and the specific welding requirements of each application. Clearweld technical support personnel can recommend the optimal Clearweld coating system for your particular application. Clearweld coatings are provided in the following formulations. Each is available in a variety of absorption levels. Clearweld Series LD120 LD130 LD140 Solvent System Acetone based Methyl ethyl ketone based Ethanol based 3

4 Requirements for a Successful Clearweld Process Accurate, repeatable application of the Clearweld material is critical to achieving a good weld. Basic requirements include the following: 1. The Clearweld material must be applied as a uniform film over the entire area being coated. Since Clearweld coatings contain energy-absorbing material, variations in film quality would result in inconsistent heating of the plastic surface. 2. Material application must remain consistent from part to part. Uniform application is an important factor for ensuring consistent weld quality and strength. 3. The Clearweld coating should only be applied to the area being welded. Any material deposited outside the weld area will be wasted. Application Methods Clearweld/EFD Dispensing Kits are the recommended application method. EFD equipment has been tested extensively with the various Clearweld materials and will provide the accuracy and consistency needed for a successful Clearweld process. Two Clearweld/EFD Dispensing Kit configurations are available: 1. A Dispense Valve/Valve Controller Kit for integration into automated or semi-automated production processes (Part No CW). 2. A stand-alone Dispense Valve/XYZ Automated Dispensing System Kit that incorporates a dispense valve and valve controller into an XYZ positioning platform (Part No. 325TT-CW). Both configurations include 10cc syringe barrels that serve as reservoirs for the Clearweld material, along with an assortment of precision dispense tips. 4

5 Dispense Valve/Valve Controller Kit The central component of both dispensing kits is the 741V-SS-CW dispense valve. This valve has been tested extensively, and is constructed of materials that are compatible with all Clearweld coating systems. 741V-SS-CW Bill of material of the CW Kit PN Description Qty 1000Y CC ADAPTER ASSEMBLY, YELLOW L AIR TEE WITH 15PSI REG/GAUGE AIR INTERCONNECT COUPLER CP-B 10CC BP KIT CLR/WHT (30) VALVEMATE 7000 CONTROLLER 1 741V-SS-CW CLEARWELD DISPENSE VALVE 1 5

6 741V-SS-CW Dispense Valve The 710V-SS-CW valve is a pneumatically operated precision needle valve. Factors that determine the amount of Clearweld material applied include valve open time, fluid reservoir pressure, dispense tip size, needle stroke, fluid viscosity and valve travel speed. When the valve is actuated, air pressure acting on the piston (1) retracts the piston and needle (2) from the needle seat (3). This allows fluid to flow from the tip adapter (4). The needle stroke and fluid flow are controlled with the stroke control knob (5). When the cycle is complete, air is exhausted back through the valve controller and fluid flow is stopped. ValveMate 7000 Valve Controller Valve open time is the most accurate and efficient way to adjust the amount of material applied. EFD s ValveMate 7000 controller simplifies valve setup and purging, and permits open time to be adjusted in increments as small as second. Momentary input of 5 to 24 VDC from a host computer or a dry contact closure initiates the dispense cycle. When the cycle is complete, an open collector circuit closes to provide an end-of-cycle signal to the host computer. 6

7 Dispense Valve/Automated XYZ Dispensing System Kit With the Automated Dispensing System Kit the valve, the valve controls and positioning functions are integrated into a compact tabletop system. Positioning and dispensing functions are programmed using the Personal Data Assistant (PDA) and intuitive graphic software included with the Kit. 741V-SS-CW Bill of material of the CW Kit PN Description Qty 1000Y CC ADAPTER ASSEMBLY, YELLOW F756TT FILTER/REGULATOR W/COALESCER 1 325TT 325MM TABLETOP ROBOT UNIVERSAL FIXTURE PLATE, 300MM TT MOUNTING FIXTURE 741/ L 15PSI BARREL PRESS. REGULATOR CP-B 10CC BP KIT CLR/WHT (30) VALVEMATE 7000 CONTROLLER 1 741V-SS-CW CLEARWELD DISPENSE VALVE 1 7

8 Fluid Reservoirs Each Clearweld/EFD Dispensing Kit includes a supply of 10cc syringe barrels. Other sizes and styles of EFD fluid reservoirs are available, depending on the volume of fluid required for the application. Volume Fluid Reservoir Capacity EFD Part No. Low Syringe Barrel 3 cc 5 cc 10 cc 30 cc 55 cc 5109CP-B (50pcs) 5110CP-B (40pcs) 5111CP-B (30pcs) 5112CP-B (20pcs) 5113CP-B (15pcs) Medium Cartridge 75 cc (2.5 oz) cc (6 oz) High Tank 1 liter 5 liter 350 cc (12 oz) DTL 626DTL Dispense Tips EFD manufactures a wide range of precision dispense tips. Tip size is described in terms of gauge, or internal bore diameter, which ranges from 14 gauge (large) to 32 gauge (very small). For Clearweld applications, 21 to 30 gauge straight stainless steel needle tips are recommended. Experiment with the different tips supplied with your Kit to determine which size is most appropriate for your application. Gauge Color ID EFD Part No. in. mm (50 pcs/box) Purple Blue Orange Red Clear Lavender B 5122-B 5123-B 5125-B 5127-B 5130-B 8

9 Setup Procedure 1. Before dispensing Clearweld coating materials, the dispensing equipment should be installed in accordance with the appropriate EFD documentation. Read all instructions carefully before attempting to dispense any material. 2. The dispensing equipment should be tested with water or alcohol before attempting to dispense Clearweld material. 3. Select one of the stainless steel dispense tips from the 741TK tip kit and install it on the dispense valve. 4. Open the stroke control knob until the reference mark on the valve body aligns with the second vertical line after the 0 mark on the scale of the stroke reference ring. Note the valve is almost closed for most Clearweld applications. 5. Set fluid pressure between 2 and 3 psi (0.14 and 0.20 bar). 6. Dispense a small amount of material to purge any trapped air from the dispense tip. 7. Adjust the stroke control and fluid pressure to obtain a slow, steady drip (1 drop/second) of fluid from the valve. Record these settings for reference. If there is a question in the future about how much fluid is being dispensed, this value can be used as a reference for the flow rate. 8. As the fluid flows from the dispense tip, it should contact the surface being coated and form a continuous bead as the tip traces the part. 9. When testing the dispensing pattern, run the program at slow speed initially, so that surface coverage can be observed and adjusted if necessary. Once proper coverage has been established, increase program velocity to the desired speed. 10. When ready to start dispensing Clearweld materials, purge all test fluid from the reservoir and fluid lines. Purge the system by either blowing it out or purge with either acetone or ethanol. If unsure, consult your Clearweld representative. 11. Verify the contents of the Clearweld container. The label of each container will list the Clearweld coating identification code. If you are unsure of what specific material fits your application, contact your Clearweld representative to verify that the correct coating system is being used. 12. Since Clearweld coating systems contain solvents that will evaporate, it is important to keep the container closed except when transferring material. Similarly, the fluid reservoir for the dispensing equipment should be capped to prevent evaporation. 9

10 13. Transfer the Clearweld coating from its container to the dispensing system reservoir. 14. Repeat steps 6-9 if necessary. Shutdown Procedure 1. If the dispensing process will be stopped for more than an hour or overnight, the air supply to the fluid reservoir should be turned off. When dispensing resumes, turn the air pressure on and purge the tip before starting to dispense. 2. For extended shutdown periods, i.e. anything longer than an overnight shutdown, the Clearweld material should be drained into its original container and the container should be capped. Be careful not to contaminate the supply of Clearweld material. i. Flush the dispensing system with solvent. The best solvent to use for this purpose is the same one used in the Clearweld material being dispensed. IMPORTANT! Any residual solvent will dilute the concentration of absorbing material in the Clearweld coating. Ensure that the fluid reservoir is free of any flushing solvent before refilling the reservoir. ii. Turn off the air supply to the fluid reservoir. If a syringe barrel is being used as a fluid reservoir, remove the syringe cap and check the condition of the sealing gasket on the cap for any tears or fraying of the O-ring. Replace as required. iii. Turn off the power to the controller. Dispense Tip Maintenance The solvents used in Clearweld coatings will normally dissolve any small amounts of absorbing material that may build up at the dispense tip. If dispensing is stopped for a short period, the solvent in the dispense tip may evaporate and leave a small amount of solid material at the end of the needle. When dispensing resumes, the first dispense cycle should dissolve this material, but a uniform coating may not be applied to the first part. To dissolve any buildup before resuming, dispense a small amount of Clearweld material through the tip or dip the end of the tip in solvent before the first dispense cycle. 10

11 EFD dispense tips can be damaged if not handled properly and should be checked periodically. Before a motion control unit is activated, insure that there are no obstacles that may damage the needle tip during movement. Troubleshooting Problem Possible Cause Correction No fluid flow Operating air pressure may be too low. Increase air pressure to 70 psi (4.8 bar). Fluid reservoir pressure may be too low. Increase fluid pressure. Stroke adjustment may be closed. Material may have clogged the valve head or tip. Wrong controller settings. Dispense tip retaining nut not tight enough. If closed, rotate one full turn counter-clockwise. Clean tip and/or valve. Check controller settings. Tighten retaining nut. Steady drip Worn needle and seat. Particle holding needle off seat. Remove tip adapter/seat assembly, clean and inspect needle and seat for wear. Replace worn or damaged parts. Sporadic drip Air bubble trapped in dispense tip Purge needle with the Clearweld material to remove any entrapped air. Fluid leaks from drain hole Fluid leaking from drain hole on side of valve indicates worn needle packing. Remove and reinstall dispense tip. Replace needle packing. 11

12 Problem Possible Cause Correction Inconsistent deposits Air pressure controlling valve is Verify that air pressure is fluctuating. constant. Inconsistent deposits Incorrect deposit width or irregular edges Air pressure to fluid reservoir is fluctuating. Air pressure controlling valve is below 70 psi (4.8 bar). Valve open time is not consistent. Dispense tip may be partially blocked. Gap height between tip and substrate varies. Amount of liquid being dispensed is incorrect. Verify that air pressure is constant. Check that air pressure is 70 psi (4.8 bar). Check for consistent output from the valve controller. Clean or replace tip. Check gap height. Adjust dispense valve and fluid pressure settings. Check that dispense tip gauge is appropriate for the application. Adjust application speed. Adjust distance between dispense tip and surface being coated. Use assisted drying to flash off solvent more quickly. 12

13 Problem Possible Cause Correction Gaps in the line Amount of material being dispensed is Adjust dispense valve and being dispensed incorrect. reservoir pressure settings. Coating beads up on parts Heavier deposit of Clearweld in one area Clearweld coating evident on sides of area being coated Gap height is incorrect. Dispense tip may be blocked or damaged. Clearweld coating used may not be optimal for plastic being coated. Contaminated part surface. Start and stop dispensing positions may overlap too much. Distance between dispense tip and part varies. Volume being dispensed is too great. Dispense tip may not be aligned with part in that area. Adjust distance between dispense tip and surface being coated. Check dispense tip and replace if necessary. Verify correct Clearweld coating system is being applied. Contact Clearweld Technical Support for recommendations. Parts may be contaminated by foreign substance that interferes with flow of coating material. Clean surface with alcohol and recoat part. Verify that valve is being opened and closed at points that minimize overlap. If points overlap, material will be deposited more heavily in that area. Check gap height in area with heavier deposit and adjust if necessary. Adjust volume being dispensed or increase application speed. Check dispensing program at point where coating runs down side of part. There may be a bow or alignment problem that requires an additional program point to align dispense tip with part. 13

14 Problem Possible Cause Correction Laser beam may not completely Check coating width and cover coated area. uniformity Excess coloration visible in welded parts Verify that laser program properly traces coated area. Clearweld concentration may be too high. Verify that correct concentration of Clearweld coating is being used. Test lower concentration of Clearweld coating. Clearweld coating isn t drying Coating coloration is not correct Significant change in deposition appearance occurs Laser power may be too low. Wrong Clearweld coating being used. Assisted drying may be necessary. Clearweld coating system may be contaminated. Material used to produce parts may have changed. Check laser power, beam, and program speed. Increase laser energy density. The various solvents used in Clearweld coatings evaporate at different rates. Verify correct Clearweld coating is being used. Add an infrared heating device to flash off solvent more quickly. It is possible to contaminate the Clearweld coating system if foreign material is added to the system. Clearweld material should be stored in its original container. If material is returned to container, ensure it has not been contaminated by other solvents. Clean out dispensing system with appropriate solvent and dispense from new container of Clearweld material. Since plastic quality can vary greatly from supplier to supplier, check source of material used to produce parts. 14

15 Problem Possible Cause Correction Clearweld material may have exceeded its shelf life. Laser energy density has to be increased Clearweld coatings have a sixmonth shelf life. Coatings can be affected by exposure to strong UV light or excessively high temperatures. Check expiration date on Clearweld container. Try using new supply of Clearweld material. Clearweld material may have been contaminated. Composition of part being coated has changed. A contaminant may have been accidentally introduced into the Clearweld container. Clean out dispenser with solvent and try coating with new supply of Clearweld material. Test weld conditions on material that has been run previously. Check for changes in composition of material being coated. Handling, Storage, and Safety Considerations Packaging Clearweld coatings are supplied in 50ml, 100ml, 250ml, 500ml and 1 liter bottles. They can also be purchased in disposable felt tip marking pens. Handling and Storage All Clearweld coatings have a shelf life of 6 months and should be stored in a cool, dry place at temperatures between 0-25 C or F. Avoid prolonged contact with strong ultraviolet light and open flames. All Clearweld coatings should be stored in their original containers and containers should be closed except when transferring material to the dispensing system reservoir. 15

16 Clearweld coatings consist of absorbing materials dissolved in common organic solvents. The amount of material that would typically be applied to a plastic substrate is approximately 80 to 120 nanoliters per square millimeter of surface area. Compared to most pastes, solvents and adhesives used in plastic joining operations, this is a very small amount of material. However, local exhausts should be used to ensure that solvent vapors do not accumulate over time within a confined operating space. When handling Clearweld solutions, common safety practices should be observed. Whenever any solvent is used, the operator should use gloves and eye protection in case of accidental splashing of solvent. Material Safety Data Sheets are available upon request. Contact Information Clearweld 6 Emma St. Binghamton, NY USA Phone Fax clearweld@clearweld.com EFD Americas: Phone info@efd-inc.com Europe: UK freephone europe@efd-inc.com This equipment is regulated by the European Union under WEEE Directive (2002/96/EC). See for information about how to properly dispose of this equipment EFD, Inc. Clearweld is a registered trademark of Gentex Corporation. EFD and ValveMate are trademarks of EFD, Inc. CLEARWELD-MAN-01 v