October 2008 Edition

productivity solutions

Making a better crusher

Software magic and new machines pulverize once costly method

Telsmith Inc., a manufacturer of rock-crushing machinery in Mequon, WI, knows what happens when there’s an unprecedented demand from mining companies responding to a dramatic run-up in metals prices compounded by a weak U.S. dollar.

With its backlog at $44 million, the highest level in decades, Telsmith has to do everything it can to meet customer demand.

Telsmith productivity tools are Edgecam software, two big CNC machine tools from MAG Industrial Automation Systems, and high-grade carbide tooling from Kennametal Inc. A third machine tool has been budgeted for late in 2008.

Responsibility rests with Dennis Van Asten, manager of manufacturing engineering, two CNC programmers (Michael Wier and David Worzalla), and the machining operators and supervisors. Their efforts embrace faster setups as well as faster machining.

The CAM programming is done with Edgecam from Planit Solutions. Telsmith has relied on the program for over 10 years, and it is the one element of the productivity program that is not new.

Telsmith’s mantra is "100 percent from the post," meaning that each program addresses everything for every job in the postprocessor. In other words, part-program editing by overly cautious machinists is a thing of the past. These "tweaks" can greatly extend cycle times and deliveries, and it takes close cooperation between Edgecam, Telsmith, and Giddings & Lewis.

Significant gains

Such cooperation led to sharp gains in productivity in just a few weeks.

"New programming methods on the existing machines have reduced most cycle times by 25 to 40 percent and in a few cases by as much as 80 percent," Van Asten reports.

That alone has generated about $500,000 in documented savings through speedier setups, he notes.

Van Asten, Worzalla, and Wier have been given the go-ahead for long overdue changes in the way Telsmith makes parts. That includes broad new initiatives in Six Sigma quality assurance and the Toyota Production System.

Telsmith makes three types of rock crushers (jaw, cone, and impact) in several sizes for mining, aggregates, quarrying, road-building and related industries, plus screens and feeders. Sales for 2007 were up sharply from 2006. Production employment stayed the same. Employees work around the clock in three eight-hour shifts plus a six-hour partial shift on Saturdays. Telsmith makes all parts in-house except bevel gears and commodity items such as bearings.

Parent company Astec Industries Inc., Chattanooga, TN, is the largest supplier of aggregate processing equipment in North America, and Telsmith is the cornerstone of that business.

The strategy

Nearly all manufacturing-technology success stories involve swapping out old vendors for new ones. This is not the case at Telsmith. It has relied exclusively on Edgecam for 10 years and on G&L for 30.

The company also upgraded its design engineering. It uses SolidWorks from Dassault Systèmes along with three licenses of Edgecam Advanced Production (milling and turning) and three modules of Solid Machinist for SolidWorks. Solid Machinist moves SolidWorks part geometry into Edgecam, minimizing the chance a programmer will miss an engineering change or small feature.

Warzalla notes that productivity gains were achieved because Telsmith, Edgecam, and G&L all worked together closely. Wier credits the successes with Edgecam, the G&L and Cincinnati machine tools, and their Siemens CNC to the three most important factors in a technology decision, "support, support, and support."

The most dramatic results for Telsmith’s multimillion-dollar investments in machining, programming, and productivity have been reductions in cycle times on the old machine tools that generated $500,000 savings.

Until mid-2007, most machining was done on eight 1980s-vintage G&L HBMs and VTLs, prompting jokes that Telsmith was "a G&L graveyard." The new G&L and the Cincinnati are the first new machines in over 10 years, Van Asten says. The new machine tools:

• A four-axis Giddings & Lewis VTC 2500 — a two-axis vertical turning center with a positioning table and a right-angle head. For CNC, G&L recommended a Siemens AG Sinumerik 840D.
• A three-axis Cincinnati vertical machining center. This also has a Sinumerik 840D.
• A third new CNC, a large multi-axis machine with integrated milling and turning was budgeted for mid-2008.

Making chips faster

The most dramatic results for the company’s multimillion-dollar investments in machining, programming, and productivity have been reductions in cycle times on the old machine tools that generated $500,000 savings, just in the first few months.

"Jobs that took a week before are now done in a day and sometimes in four hours," says Van Asten. "The machine operators compiled the numbers themselves and at first they didn’t believe it."

Workpieces done on the new machine tools have averaged 60 to 80 percent shorter cycle times. First, jobs no longer sit idle with spindles turning the air during tweaks and edits. Also gone are overly cautious feeds and speeds, a big factor in Telsmith’s long machining cycles. With Edgecam programming and upgraded cutting tools, feeds and speeds have increased tenfold.

"We have to make sure the program works and is clearly understood no matter how fast it cuts," Wier says. "We are using Edgecam to its fullest potential."

Two examples:

In-program probing macros— dozens of fully automated probing cycles per part program. Done before almost every tool change and new cut, these macros help eliminate the risk of a tool crash.

Previously, each probe took five to 10 minutes. Probing now takes 30 seconds so much more probing is done. Probe data is automatically fed back to the postprocessor, eliminating one more potential error risk and one more set of tweaks.

Threading macros— 42 pages of them and variables for threading, in particular for buttress threads. With their asymmetrical cross-section, buttress threads are best to withstand the shock loads, vibration, and high stresses in rock crushers.

Precise programming also means long hours in the shop. Many of these hours are spent with the machinists.

"We want the machinists to give us feedback on how the new programs run," Wier says. "We feel these extra efforts will make a good machinist twice as good."

Return on investment

One of the most significant Telsmith
achievements has been financial — cutting the anticipated ROI on the two new machine tools to about 18 months. The original projection had been for up to six years.

Big customers were also impressed.

"We had representatives here from Caterpillar when we ran off the G&L," Van Asten says. "They were amazed at what we were able to do. Even the people from Kennametal were impressed, and they were partnered with us all the way. This has been a huge success for us and the word is getting out. Three of our sister (Astec) plants have sent people here to see what we are doing.

"The Toyota Production System and Six Sigma are good and I would not want to be without them. But to really advance, you have to embrace machining technology wholeheartedly."

Van Asten and his team did something more than just install new machinery, processes and methods at Telsmith. They have installed, or perhaps better reinstalled, the ingenuity that made American manufacturing a world leader in the first place.

Edgecam

MAG Industrial Automation Systems

 Kennametal Inc.

Postprocessors are crucial to CNC productivity levels

The challenge of writing postprocessors, or "posts," is the technical complexity of the state-of-the-art machine tools. An integral part of the CAM system, the post translates the programmed motion of the cutting tool into G-code that machine tools "understand."

Postprocessors can be the Achilles heel of productivity of new machine tools. If mishandled, they are the weakest link in the chain of software and interfaces between design and manufacturing. Hundreds of individual machine-tool functions must be addressed with each command routed through thousands of electrical and electronic input/output (I/O) points that connect the CNC to the machine tool’s servo drives.

Every machine tool action and every cycle sequence goes through that I/O maze — spindles and cutters; all worktable and travel in the machine’s drives; synchronizing those three/four axis with each other and with the spindles and cutters; circular and linear interpolation, brakes, stops and limit switches; and myriad other functions of tool changers, work holders, dimensional offsets, sensors, instrumentation, coolant on-off, safety interlocks, CAM program download, and so forth.

"Postprocessing is a big thing for us," says Michael Wier, CNC programmer at Telsmith Inc. "The Edgecam postprocessor module, Code Wizard, lets us change the posts and work with them effectively. That makes it easy to adapt existing programs to small engineering changes."

Wier and fellow programmer David Worzalla wrote the post for Telsmith’s second new machine tool, a large three-axis vertical machining center from MAG Cincinnati.

What do you think?
Will the information in this article increase efficiency or save time, money, or effort? Let us know by e-mail from our website at www.ToolingandProduction.com or e-mail the editor at dseeds@nelsonpub.com.