With 15 manufacturing operations in North and South America, Europe and Asia — along with some 2,000 employees — Autocam is a particularly successful company. It started with a few Tornos lathes more than 25 years ago and achieved sales of $300 million in 2013.
At its Kentwood (Michigan) headquarters, the company manufactures ultra-precision stainless-, alloy- and tool-steel components for fuel systems, braking systems, transmissions and other automotive parts on its Tornos machines, of which it has more than 200 globally.
Mike Clay, Autocam’s technical and quality director, says: “We are turning to tolerances of ±10µm — and better. The majority of our components are used in advanced fuel systems such as GDI — gasoline direct injection — and high-pressure diesel. Many of these parts have complex geometries and are made of materials that are very challenging to machine.
"To maintain our leading position, we need ultra-precise and rigid machines that optimise process reliability and allow us to make products of the highest quality at a competitive cost, so the relationships with our machine tool suppliers are very important to us.”
When Autocam was considering adding two more CNC twin-spindle machines to increase production of a particular direct-injection pump component at its Kentwood facility, Frank Zacsek (manufacturing quality engineer) and Matt Tufer (senior technician) convinced their colleagues to consider Tornos’s new MultiSwiss machine (
www.tornos.com).
Mr Clay says: “The interesting thing about this part is that the volumes did not require a fully equipped multi-spindle CNC; but because we still required the highest levels of precision, it made sense to compare the MultiSwiss with a bank of CNC twin-spindle machines.
My reckoning was that if we could achieve the required production levels on one machine for roughly the same manufacturing cost as several single-spindle machines, it would be a better process for us and for our customer.”
Minimised handling
With high-precision components for direct fuel injection applications, surface damage to a part must be avoided — the less material handling and moving between machines the better.
Mr Clay says: “The more we have to handle a part through successive operations, the more opportunities there are for damage. The philosophy of our CEO — John Kennedy — is to stay on top of technology; and if there’s a better technical solution that improves quality or reduces
the variation, we should pursue that, even if it entails spending more money.”
The cost of one MultiSwiss was higher than the cost of two twin-spindle machines; but Autocam thought that the ROI on the MultiSwiss looked promising.
“With the MultiSwiss, we were able to develop processes that finished critical dimensions — particularly regarding surface finish and flatness,” says Mr Clay. “Moreover, we can complete parts on the MultiSwiss, where other companies would have to undertake an additional face-grinding operation.”
The fact that the parts do not have to travel from machine to machine to complete all the necessary operations, but instead stay in the MultiSwiss where turning, drilling and milling are done sequentially at six spindles — each with up to three tools — means that the possibility of damage is minimised.
Pushing the boundaries
Discussing the MultiSwiss programme at Autocam, Tornos sales engineer Tom Broe says: “We were pushing the boundaries of the MultiSwiss with the injection part we were asked to trial. It is not an easy part to produce; there are some tight tolerances, and the 440C material is difficult to machine. However, Autocam’s CEO said that if we could satisfactorily produce the part on a MultiSwiss, he would order a machine.”
The part, which is 7.3mm in diameter x 24mm long, requires turning, drilling and milling operations; and with tolerances of ±30µm on the length and ±20µm on outer diameters, it was near to exceeding the length-to-diameter ratio for accurate machining.
Mr Clay says: “Tornos’s product manager Rocco Martoccia knew from the tolerances and cycle time targets that we had to hit, combined with the material and part geometry, that the trials were going to be challenging. He was up-front about this.”
Tornos worked with Autocam to develop the process and optimise the feeds and speeds to achieve the required quality and throughput (on the MultiSwiss, each spindle position can be programmed independently).
Mr Zacsek said: “We had two of our engineers in Switzerland for about three weeks. To develop this particular process, both organisations worked together to make it a success. When we encountered issues, neither of us walked away; together, we developed a robust process that is now working well for us in Michigan.
“One of the good things about the MultiSwiss is that you can optimise the spindles, which will allow us to hold even closer tolerances on future products. Another good point about this machine is that the tools are a little bit higher than those on a standard multi-spindle, so you’re not bending over quite as much; and when you open the door, everything is right in front of you, which is much better for our machinists.
“Ease of use is very important to Autocam. The learning curve is generally much steeper for machinists on multi-spindle machines, but the MultiSwiss does not appear threatening. The way the machine is laid out means you can break the various processes down in your mind pretty quickly. Indeed, the MultiSwiss is comparatively easy to understand and operate.”