Why a tool and die maker "collects" SORALUCE milling machines
Performance and precision in XXL format
An owner-managed tool and die making company based in Neuenstadt with just two dozen employees has been using a total of ten large-sized SORALUCE milling machining centres over the past 22 years. This is quite unusual for a company of this size. Reason enough to inquire about how this brand loyalty came about and what motivated the owner to opt for a portal milling machine instead of the previously preferred moving column machines.
“Our most important line of business is the production of high-precision prototype and series tools for customers such as Daimler, Audi, Lamborghini, Porsche, ThyssenKrupp or Voestalpine,” explains Karlheinz Weiß, owner of Weiß Metallbau GmbH in Neuenstadt-Stein near Heilbronn.
In 1991, after passing his masters examination, he started what you would almost call a proverbial “garage company” as a second job, which he quickly, also with the energetic support of his wife lrene and his brother-in-law Harald Pezzi, built up into a flourishing company which today has 24 employees. The main field of activity is the production of large-size press tools for car body production in the automotive industry. With the help of such press tools, automotive manufacturers produce sheet metal parts for bodies from wings to doors, bonnets and side frames. Prototyping tools are usually made of cast iron, while series tools are fitted with inserts of high alloy tool steels containing chromium, molybdenum or vanadium components.
Special machine and jig building
“Another business area is the production of special machines for the company KS Kolbenschmidt”, adds Harald Pezzi, Operations Manager at Weiß. This is a licensed production of special lathes for finishing the bolt holes of pistons for internal combustion engines.The machines are based on patented developments and are only used in their own companies all over the world. The quality of machining these holes determines the durability of the pistons and therefore the life of the motors, which in turn implies the highest possible precision in the manufacture and assembly of the machines used for this purpose. Weiß also manufactures welding, joining, gluing, handling and processing equipment in this field.
The SORALUCE PMG 6000 at Weiß
The SORALUCE PMG machine is a Portal milling machine for heavy duty machining of large sized workpieces with a table length of 6,500 mm; table width of 2,700 mm; distance between the columns of 3,705 mm and a height from the table to the underside of the cross rail of 2,450 mm.
The specification of the machine at Weiß includes an in line Desch motor with 60 kW of power and up to 2,000 Nm of torque; the DAS+ system for vibration damping; an automatic stepless indexing milling head with spindle speeds of up to 7,000 rpm, vertical milling head with spindle speeds of up to 4,000 rpm, vertical HSC-milling attachment for speeds of up to 26,000 rpm, automatic head changing system and a head pick up station with spaces for all of the 3 milling heads.
Stricter requirements necessitated a change to the portal machine
“The purchase of the especially large SORALUCE portal machining centre is due to the machine equipment being supplied, extremely flexible and is an investment in our future. This is the largest investment in the history of our company. As we have complete faith and trust in the managing director Mr. Andreas Lindner we chose the PMG. Our business relationship has developed and grown into a partnership over the last decades.” explained Mr. K. Weiß.
The market always demands the highest quality from him, faster turnaround times and lower costs. That’s why he decided for the first time for a portal milling machine instead of the hitherto preferred travelling column machine design. Thus, the stricter accuracy requirements of customers in the region of 0.02 mm could be fulfilled more easily, and also the resulting machined surface finish is also significantly improved. In addition, the machine concept of the portal machine was convincing because the parts could be clamped more easily in a vertical position – which also corresponds to the installation position in the press shop. After all, you save several hours of set-up time on each workpiece, as also other component parts of the complete tool can be assembled into the main bodies inbetween individual machining operations and then finally the machining of both elements can be carried out at the same time.
In the present case, it proved to be favorable that the new machine fitted almost perfectly into the place of the previous machine. Only minor changes had to be made to the foundation, which was planned by BIMATEC SORALUCE during the bidding phase. From the height, however, it was so tight that only 25 mm of space remained between the very top of the machine and the crane bridge and corresponded exactly to the plans from Bimatec Soraluce.
Characteristics and features
“The SORALUCE milling head technology, which we have known for more than 20 years, is one of the key arguments in favor of the SORALUCE machine,” affirms K. Weiß. The machine is equipped with an HSC milling head, vertical milling head and a stepless indexing milling head which delivers a power of 60 kW at 7,000 rpm.
For high-precision finish machining, the HSC milling head with 26,000 rpm is installed on the machine. The control system of the latest generation now ordered automatically compensates for typical disruptive factors such as thermal deformation of the machine or sagging of the vertical saddle and the cross rail.
During the purchase the decision was also taken to equip the machine with some additional options, which mainly benefit the user giving optimized machining processes. These include chatter suppression DAS+, Adaptive Control and user-specific custom cycles.
- DAS+ a further improved development in the technology for the dynamic compensation of chatter vibrations during machining. As soon as sensors detect the typical vibrational patterns of chatter, actuators in the machine ram generate corresponding counter-frequencies. This effectively suppresses chatter. The newest version DAS+ detects and compensates for different variants and can also optimise the spindle speed and the feed rate in such a way that chatter is prevented from occurring. The result is better surface finish and significantly reduced tool wear.
- An optimal supplement to DAS+ is Adaptive Control, a fully automatic feed control that adjusts the feed rate in respect to the usable spindle power, depending on the material allowance. This avoids tool breakage and optimizes the efficiency of machining.
- The user specific custom cycles developed by Soraluce are hands-on software tools that make the job easier for the operator. This includes additional softkeys, diagnostic masks and apps for easier programming and operating of the machine.
„As with all of the other machine installations, the delivery, assembly and commissioning happened quickly and without problems,”, stated K. Weiß. BIMATEC SORALUCE were perfectly prepared, so that the assembly work could be completed in just six weeks. Since then, the machine has been in operation without significant interference. As an example, he can now machine side wall frames which have a size of 4,800 x 2,480 mm with an accuracy of 0.02 mm for the plate guideways and bored holes for column guides.
Astonished by the precision in the finishing process was his son Leon, who after completing his apprenticeship as a toolmaker at a large automobile manufacturer, is now active in the field try out area. “When I have time, I help my father with the surface polishing of the tools and I am surprised or more to say astonished about the new SORALUCE portal milling machine. This is so exact and precise in the surface finish machining that we save about a quarter of the time when stripping and polishing, especially in the radius transitions”, so his conclusion.
Klaus Vollrath b2dcomm.ch