Machines SERDI s.a. 23, avenue des Vieux Moulins B.P. 380 74012 Annecy Cedex France Tél. : (33) 04 50 65 63 00 Fax Direction : (33) 04 50 52 99 95 Commercial : (33) 04 50 52 99 92 Bureau d Etudes : (33) 04 50 65 63 12
1. Introduction World leader in the area of the cylinder head, thanks to its patented centering systems on air cushions, Serdi had to be the leader in the machining system cutting by interpolation. Due to continued technological innovation of the engines, Serdi noticed a growing demand for machines capable of machining valve seats with materials getting always harder. This development will continue in the coming years that s why Serdi offers new solutions adapted to this environment. To achieve this goal, Serdi joined a German leader in production of precision tools: Komet. This large German company has recently developed induction motors to generate and control movements of the U axis. This patented system called Komtronic. It has been used until now mainly on CNC machining centers. Among the Komtronic s customers are in particular OEM vehicle manufacturers. Serdi had the idea of associating Komet in the development of its new machine designed for rebuilders or tuners. Thus was born the STroniK, which is based on the intrinsic knowledge of each partner. The STroniK is a machine of high accuracy designed by combining the cutting edge technology of the machine tool in terms of mechanics, CNC control and power motor. The reliability of the STroniK is guaranteed by the fact that each component of the machine has been used in other applications for several years. Serdi opted for an open numerical control system by choosing a product market leader, ie Siemens. This choice has the advantage of enabling the client to be independent of Serdi for the numerical control. The STroniK mainly uses Siemens products for its motor and electronics creating a favourable environment for a quick and reliable customer s service. The competences of each partner in the areas of OEM manufacturers are the guarantor for the respect of the norms and for an optimal integration of the different components. The joint work of Serdi and Komet s research teams and development allowed the register of a patent owned equally by each partner. This patent recognizes the industrial excellence of the STroniK which should remain as a market leader for many years. 2/
2. Constraints and solutions chosen. The use of alloy materials in the structure of the valve seats requires cutting parameters with high speeds for smaller diameters and lower speeds for machining large diameter seats. It is therefore imperative to have a spindle for obtaining high speeds and a high torque at low speed. The STroniK meets these conditions with a 4 KW in built spindle motor with a maximum torque from 0 to 3,000 rpm, and the ability to go up 5,000 rpm. The concentricity and surface condition of the valve seat are important criteria to allow good contact and a tight seal between the valve and seat to ensure the cooling of the valve and good engine performance. To do this, all elements of the machine must be sufficiently rigid and the movement of the cutting tool must be regular and with no play This result is obtained if the motion commands of this tool follow the instructions given and the backlash are minimum and stable over time. In addition, the mechanical components must be reluctant to deformation and wear, and temperatures generated by the motor must be minimal. The STroniK satisfies all these requirements. The induction motor does not create backlash with minimum temperature rise. The hollow spindle motor has an integrated cooling which can be activated if necessary. The STroniK allows maximum use of the machine without creating high temperatures. The profile of the seat must be maintained, it is important that the interpolation of axes U and Z to be regular and constant. This interpolation requires control elements of these axes. The STroniK and Siemens CNC will achieve the desired result for any form of seat and pre chamber channels. Finally, the weight of embedded system should be minimal. The technology of the transfer control signal and power induction developed by Komet has helped to minimize the weight and define an optimum location of motor control units and movement of the tool. The Komtronic system, including the induction motor and linear motion, weighs only 7.2 kg. This weight is distributed equally above and below the sphere, which allows handiness and a self centering of high accuracy. 3/
The seats profile can be very wide. This parameter requires to have a sufficient U displacement of tool; the 22 mm radius stroke of the Komtronic machining head should cover all needs. To ensure maximum rigidity and prevent deformation, the bed has been designed in cast iron. The STroniK allowed a reliable integration of leading edge technologies controlled by a CNC tool which guarantees the best machining results for a wide range of cylinder heads. 3. Devices specifications U axis induction motor The power system and control induction motor for the movement of the U axis (patent Komet), located on the top of the spindle, has enabled these elements to be located directly into the rotating elements of the spindle. The system also limits the number of mechanical transmission of rotational motion into linear motion located at the bottom of the spindle. Regular displacements and without overload of the tool-slide, whatever the type of material, with cutting feed up to 300 mm / min. can be obtained through a brushless motor powerful enough. The 115 mm outer diameter of the Komtronic head and the configuration of the cutting tool enable all types of machining on small and large heads. The machining of large seat width, without the need of recovery point, is possible thanks to the 22 mm radius tool travel and despite the compact external dimensions of the machining head. The STroniK can perform simultaneously intake and exhaust seats machining without tool holder change. This 22 mm U displacement combined with the 245 mm spindle stroke makes possible the machining of deep profiles encountered on the high speed diesel engines or high performance engine ports (venturi). 4/
The spindle stroke 245 mm allows the combined machining of the seat and guide bore with lengths exceeding 100 mm. The lubricant supply from inside the head will guarantee to keep the tolerances of the bore, while increasing the life of the reamers. Thanks to the positioning of the tool on the ridged tool carriage, the machining capacity of the seats will be from 14 mm to 163 mm. This technology, already proven in industrial applications by manufacturers and on different materials, provides a reliable solution to the expectations of customers concerned by the remanufacturing or development, who are looking for a high precision tool capable to meet the quality criteria equivalent to those of the manufacturer. These same customers will also benefit from the experience gained by Komet in the material cutting process to bring them the solution in the selection of the tools. Motor built into the sphere This type of synchronous hollow shaft motor, integrated into the spindle, has been developed for applications of CNC spindle machine tools. The integration of the motor inside the spindle requires compact dimensions. This integration was made possible by the choice of that type of motor having a torque which, with equal volumes of the active part, is 60% higher than conventional motor. The hollow rotor "rare earth" magnets, generates little power dissipation in the rotor, which reduces the heat and expansion of the spindle. The optional motor cooling system ensures, if necessary, the control and maintain of the spindle operating temperature. Therefore the STroniK can be used in demanding environments, such as those encountered in industry or countries with extreme temperatures. The torque value and acceleration can achieve a high machining accuracy due to the regularly and accurate rotation of the spindle, even at low speed, this because of total lack of transmissions. A spindle speed encoder enables precise control of speed and torque. 5/
CNC Z and U axes are digitally controlled by a standard CNC product range of Siemens 802D / 840D, in total agreement with the displacement motors of these two axes. The 802D CNC can accept up to 5 axes and a spindle, which should be sufficient to perform the commands necessary to achieve the machining of the cylinder head in an automatic cycle. For larger applications, the 840D CNC meets all requirements. The programming language is in accordance with ISO standards. This standardization of parameters allows rapid adaptation for people trained in standard CNC controls. On the other hand, the choice of the CNC, used in many countries and in different environments, will benefit from additional service structure to that of Serdi and ensure the sustainability of the machine. The partnership between Serdi and Komet will also ensure a continuous development of the product, always in accordance with the needs encountered at manufacturers, both in terms of technical development of engines as the means of production required by industry. 6/
NUMERICAL CONTROL "U" AXIS WORKHEAD SPINDLE "Z" AXIS STroniK StroniK XL COMMENTAIRES CNC Type SIEMENS 802 D SL Pro SIEMENS 802 D SL Pro Optionnal SIEMENS 840 D Programming system ISO ISO Number of numerical axis 2 numerical axis "Z" and "U" 2 numerical axis "Z" and "U" Possibilité de commande d'axes 5+1 spindle 5+1 spindle If 840 D, possibility to control 31 axes Available language 18 18 Automatic displacement of the tool holder - on radius 22 mm 22 mm Pilot locking system by screws Machining capacity 14-163 mm 14-163 mm Number of workhead to cover the machining range 1 1 Tool feed speed 0 à 300 mm/mn 0 à 300 mm/mn Centering system Triple air cushions Triple air cushions Sinpdle tilt 5 5 Vertical re centering of the spindle by pneumatic jacks Sphere cylinder displacement + / -' 6 mm + / -' 6 mm Horizontal re centering of the sphere cylinder by pneumatic jacks 990 mm 990 mm + 500 mm parking space for the Maximum displacement 1 300 mm :optionnal loading/unloading Spindle motor power 4 KW = 5,5 HP 4 KW = 5,5 HP Direct drive by synchronous hollow shaft motor with permanent magnet, integrated cooling system Rotationnal speed (with maximum torque) 0 to 3000 rpm 0 to 3000 rpm Speed controlled by encoder Maximum speed 5000 rpm 5000 rpm "Z" spindle travel 245 mm 245 mm 300 mm optionnal Feed 0 à 10 000 mm/mn 0 à 10 000 mm/mn Valve guide reaming stroke > 100 mm > 100 mm Possibility to achieve combined machinings of the valve guide and valve seat Depth correction control system stroke 100 mm optionnal 100 mm optionnal By non reflective laser Increment 0,01 mm 0,01 mm OTHERS Cooling direct through the spindle : optionnal BED Material (bed, columns, upper beam) Cast iron Cast iron Installed on a tubular frame CYLINDERHEAD CAPACITY Height 475 mm 968 mm Height between the pilot housing and table bars DIMENSIONS WEIGTH SUPPLIES Longitudinal workhead displacement (Maximum travel between guides) Length no limit min 930 mm/max 1430 mm Width 500 mm min 530 mm / max 790 mm Weight 400 kg 400 kg (2 000 kg optionnal ) Y displacement of the table bars 160 mm on table with air cushion 160 mm on table with air cushion on linear ways : optionnal Sindle motor cooling Floorspace requirement Heigth (spindle at the maximum upper position) 2 310 mm 2 320 mm Maximum length (without CNC cabinet) 1 835 mm 2 165 mm Depth 1 150 mm 1 150 mm CNC cabinet dimensions L x l x H en mm 600 x 520 x 2 020 600 x 520 x 2 020 Net weigth of the machine 1 560 Kg 1 750 Kg Electrical 3 x 400 v + N + PE, 50/60Hz 3 x 400 v + N + PE, 50/60Hz Power 6,3 KVA 6,3 KVA Pneumatic 6 bar 6 bar integrated air - water : optionnal 7/