How Cam Replaced Cams in Swiss-Machining

One expert's view on the paradigms that have given rise to the importance of CAM software in CNC Swiss-machining

Time was that when "CAM" was said to a CNC Swiss-type lathe user, the first thought that came to mind was the CAMs on a Screw machine. Not any more.

Today, Computer Aided Manufacturing (CAM) software has become as critical a tool to shops involved in CNC Swiss turning as it is to those involved in milling. Just a decade ago, CNC Swiss machines were essentially all programmed manually. Today more and more Swiss shops are turning to CAM software to automate their CNC programming.

This fact gives rise to the question: What was it that changed to make CAM software such an important facet of Swiss-machining?

The answer: A lot has changed!

Here are some of the major paradigms in CNC Swiss-turning that have lead to the rise of popularity of CAM software.

Focus on Set-up reduction

A decade ago, virtually all CNC Swiss machines were dedicated to high-volume production. Once a job was set-up, it would run weeks, if not months at a time. By 2000, that situation had started to change with the proliferation of "Just In Time" and "Lean" manufacturing initiatives as well as the increasing influence of low-cost foreign competition. Lot sizes have been dwindling ever since.

As a result, the remaining jobs left for CNC Swiss machines were smaller in volume and more complex to manufacture. The increasing complexity came in the form of more milled features and more stringent tolerances.

As recently as 2003, I remember speaking with a customers - a major production job shop with a number of Swiss machines in the Cleveland area - and the owner lamenting these trends to me, saying, "My customers are demanding the same price for a part we were providing four years ago, except that part now has a number of additional features and they are ordering them in quantities of 50 not 5,000."

These two trends meant that setting up a job quickly became more critical than ever. If a part runs for six months, and its setup takes an extra few hours, the profitability of that job will not be severely affected. If a job runs for six hours and its setup takes an extra few hours, now you're running those parts for free.

With the right CAM system, Swiss shops found that instead of programming right at the machine or programming manually off-line and painstakingly proving out the program at the machine, they could generate the program off-line, visually simulate the machining process on a PC and send a program which required little if any operator intervention to the machine.

In a number of cases, users who have switched to PartMaker Swiss- CAM from manual programming have reported reducing machine setup time by over 50% in the first 30 days of implementing the software.

Though the idea behind CAM software is to speed up programming, for CNC Swiss, often the biggest benefit a CAM system provides is that of setup time reduction.

More axes, more problems

CNC Swiss machine builders didn't just sit idly by while their customers toiled with smaller lots sizes and more complex parts. They reacted to these trends by building machines better suited to complete complex parts in one setup. What this meant was that Swiss machines increased in complexity. More tooling slides were added and milling capabilities were beefed up. Today, some Swiss machines have in excess of 13 programmable axes, up from the high end of about 5 a decade ago.

Of course all these axes needed to be programmed and controlled. Needless to say programming a 13 axis machine is a lot more difficult than programming a 4 axis machine. This new breed of machines, virtual "machine shops in a box" -- as William Hulbig, founder of Micro Group, a contract manufacturer in Massachusetts calls his Citizen M-20 machines, -- increased the emphasis on decreasing setup time. With increased complexity came increased cost, and the cost of machine downtime increased accordingly.

New machine tools have been developed, such as the Star ECASD-32T that features two turrets and a back working slide and the Tsugami TMU-1 with an upper B-axis head and lower turret. These mark the conversion of the Swiss-type lathe from a CNC Screw machine to a fully enclosed small parts processing cell.

As a result more shops felt the need to move to CAM software to help them harness the power of their equipment and automate their programming.

Technological Innovation

While the ever increasing focus on setup reduction was forcing Swiss users to find a way to automate their programming, what they often found was disappointment and broken promises.

The problem was that the world of CAM was, and by in large still is, milling-centric. CAM software has traditionally existed for milling applications, while turning has long been the red-headed step-child of the CAM world. The programming requirements of CNC Swiss-type lathes vary greatly from a mill or 2-axis lathe. Many CAM vendors approached the problem of programming a multi-axis Swiss lathe as simply adding milling and turning together. Unfortunately, mill plus turn does not equal Swiss.

Lee Dwyer, Vice President of Starro Precision Products of Elgin, Illinois, notes that, "Prior to purchasing Part- Maker SwissCAM, we did a robust analysis of nine other software solution providers as well as discussing the best application with each machine tool manufacturer. In many cases we found they were not able to provide any real solutions for programming our CNC Swiss-type lathes. After doing the analysis, PartMaker SwissCAM surfaced as the solution for programming our machines," Starro has over 35 CNCs including various models of Star and Citizen Swiss-type lathes in addition to CNC Mills and fixed headstock lathes with live tooling.

"We've found PartMaker SwissCAM to be a savior and have increased our output 300% regarding programming and part qualification. We are pleased to say, that 4 yrs. after acquiring the software, the decision to partner with PartMaker SwissCAM has been reinforced by the constant successes we have achieved," continues Dwyer.

PartMaker SwissCAM appeared on the market in 1999 as the first CAM package specifically dedicated to programming all models of Swiss machines. Though SwissCAM's core technology is based on IMCS's patented technology for programming fixed head stock Turn-Mill centers, SwissCAM went far beyond just programming turning with live tooling. It included support of Swiss specific programming issue such a sliding headstock, tool shifts and process synchronization of multiple tools working on a main and sub-spindle.

Many leading Swiss users including such industry leaders as Medtronic and Corning (as well as number of smaller ones) caught on and have standardized their programming on PartMaker SwissCAM.

Help Wanted

While part and machine complexity continues to rise, the availability of experienced personnel with a command of Swiss-machining has not kept pace, and in fact, is in short supply.

Generally speaking, software has always been a tool not just to automate tasks, but to lend expertise in carrying them out.

This general truism applies to Swiss machining. The explosion in the popularity of Swiss machining - an expansion driven by growth industries such medical devices and telecommunications - has increased the number of companies requiring help in automating programming. Many shops that are new to Swiss but long on experience in traditional CNC applications have turned to CAM to speed their transition into CNC Swiss manufacturing.

Solid Modeling

Another paradigm that has increased the need for CAM software among users of CNC Swiss-type lathes is the proliferation of solids design. It is becoming increasingly more common that part data is provided in the form of a Solid Model versus a traditional paper drawing. Solid models help the part designer by better envisioning the part as well as making that part available to fit into an assembly or for use in finite element analysis. As more of the parts being machined on Swiss machines have gone the way of solid modeling, the need has increased for manufacturers to adopt programming methods to accept data in solid format. A CAM system allows a manufacturer to accept a Solid Model design and apply machining strategies to generate an NC program. TMD