It still amazes me how small some of the parts can be in our industry. Earlier this year I visited a shop in Barrington, Ill. (near Chicago) that runs a large range of products, from hydraulics to medical to aerospace to connectors. While the majority of my visit focused on Swiss Automation Inc.’s highly effective solution to hiring and training operators (see “A Swiss Shop’s Next Generation”), Foreman Marc Moran seemed proud to show me around the shop floor, sharing other cool things the company is doing to keep pace with the competition and meet customer demands.
One of the company’s strengths is its ability to deliver precision parts of various sizes quickly. All parts produced here come off of the machines complete, with no secondary operations. The part pictured above was made on a Deco machine from Tornos Technologies U.S. This medical component has an 8-thousandths hole through it with four mills along the sides. Marc says, “It’s almost like a sliver. It looks like just a chip from one of our other machines.” I know I have weak eyes, but I can barely see anything in Marc’s hand.
Producing these tiny parts is only part of the equation. Equally challenging is the inspection process, verifying that they meet the quality standards. With inspection stations strategically placed throughout the shop floor, as well as two quality control rooms, Swiss Automation takes its inspection processes seriously. In fact, all new shopfloor employees and apprentices begin in this department to get a fundamental understanding of its significance.
The tolerance on cold-drawn steel bars for machining is always specified as plus nothing minus some value. So why are the dimensions on the bars held to the minus rather than plus side? Don’t we want to get more steel per foot for our money? May I have your answer please? The reason for the dimensions being held to the minus side is so that the bars can easily pass through a hole of nominal size.
If the bars were the same nominal size as the hole, they would be difficult to assemble. If the bars were even slighty larger, they would not pass through.
So bars are held to the minus side of each nominal dimension to ensure that they can pass through the nominal size hole, whether it be a bushing, pulley, gear, collet, support bearing or any similar application. The bars must measure less than the nominal hole size to permit assembly.
How did this come to be? Line shafting. The power transmission shafts that ran across the ceilings of shops while being held in bearings were called line shafting. The power was taken from the shafts by belts and pulleys. The shafts were held by bearings affixed to the ceiling joists. The shafting had to fit into these bearings and pulleys. (These shafts were driven usually by a single large motor, steam engine, or water wheel.)
It has been some time since power transmission shafting has been used commercially to drive our lathes and drills commercially.
But we have the legacy of cold finished shafting to thank for the foundational concept of tolerances on bar products being held to the minus side.
Thanks to John Halladay at PMPA technical member Vectron in Elyria, Ohio, for the archival shop photo from the Perry Fay Company.
And if you have a burr problem with some of your production, you can call on Vectron to help you with that, too.
Do you have memories of working with machinery driven by line shafting in your career? We’d love to hear your story.
Tooling supplier Techniks offers a “Machinist’s Guide to Toolholder Maintenance,” a 5-page overview of some of the most important aspects of keeping collet-and-nut-style toolholders in top condition. Proper toolholder care, according to the company, is one of the most cost-effective ways to increase machine productivity, protect equipment investments, and reduce downtime and scrap without sacrificing part quality. Unfortunately, inexperienced machine operators might not know how to recognize when components of collet-and-nut-style toolholder assemblies need to be replaced or might not fully understand the importance of doing so. To read more about the guide, visit “A Machinist’s Guide to Toolholder Maintenance,” or visit the full guide online that includes toolholder terminology and concepts.
I recently returned from a trip to tooling manufacturer PH Horn. The event was the company's biennial Technology Days held at the company headquarters in Tubingen, Germany.
As with past events, customers, agents and press members made up the assembled crowds during the 3-day event. In addition, 11 outside companies including machine tool builders, workholding manufacturers and accessory vendors participated with technology demonstrations on the factory floor.
For me, the technical presentations are a highlight of my visit to the company. They are done in English, which is very helpful for me, of course. As your traveling proxy, I plan to publish articles in coming issues of Production Machining so you, too, can learn some of the new things coming out of this company.
Some of the topics we will cover include high feed-rate machining, ultra-hard cutting materials, broaching on CNC machines and a discussion of indexible insert manufacturing using injection molding techniques. In the mean time, please click here to visit the company website for more information.
Displays of cutting tools were located throughout the manufacturing facility which was open to visitors from around the world.
In addition to the Horn products 11 suppliers, including Tornos, participated in the event with demonstrations on the shop floor.
Gibbs' postprocessors support a large variety of multitasking machines.
Gibbs and Associates, developer of GibbsCAM software for programming CNC machine tools, recently delivered its 1,250th postprocessor in support of a large variety of multitasking machines (MTMs) from nearly 70 manufacturers. Each postprocessor is uniquely developed and configured for a specific combination of MTM, machine options and control.
Most MTMs require a CAM system capable of programming the complex combination of milling and turning while synchronizing the motion of multiple tool groups and spindles with part transfers and release, all within a restricted space. According to the company, GibbsCAM offers post-processors to generate CNC code that optimizes machine tool efficiency and accommodate shop-process preferences. The library of MTM post-processors, in combination with GibbsCAM software, allows customers to take full advantage of the productivity offered by MTMs.
“When new machines and new machine capabilities are introduced, we broaden GibbsCAM’s programming and post-processing functions to accommodate them,” said Robb Weinstein, senior vice president of sales and strategic planning of Gibbs and Associates. “Then we develop and deliver error-free post-processors, and maintain them ourselves, to ensure that our users never need to edit the output. This helps customers attain the highest levels of productivity in programming and machining and strengthens our relationships with our multiple machine tool partners.”
Gibbs has a staff dedicated to developing, implementing and maintaining post-processors. This post-processor group maintains a current library of nearly 11,000 unique post-processors to accommodate all types of lathes, mills, multitasking machines, and their associated controls.