Developing an effective offline tool presetting strategy requires careful planning, an open mind and a good handle on what’s available.
With the number of offline and in-process toolsetting options on the rise, developing a way to efficiently utilize this technology can be confusing. Which presetter should we buy? What about the software that’s so often part of these systems—do we really need it? Why not save a few bucks, eliminate the presetting fuss, and simply probe tools on the machine? For that matter, what’s wrong with staying old school and touching off tools manually, just as we’ve always done?
Close to Perfect
Brendt Holden, president of Haimer USA LLC, offers insightful responses to several of these questions. During an open house earlier this year at Haimer’s Villa Park, IL facility, he listed a number of benefits of offline tool presetting, starting with consistency. “Unlike traditional methods of toolsetting, where the accuracy depends largely on the operator’s skill level, presetters provide repeatable results,” he said. “Whether it’s someone with 20 years of experience doing the measuring or a newbie with two weeks under his or her belt, tool dimensions come out exactly the same, each and every time.”
Attaining highly accurate tool measurements is all well and good, but any machinist will tell you it’s often irrelevant. Machine tools aren’t perfectly square or level, a phenomenon that only increases with age. The shop might be cool in the morning and hot like the desert in the afternoon. Cutting tools and workholding deflects, especially so when machining superalloys or removing large amounts of material. Added together, these and other variables mean that test cuts and subsequent in-process tool adjustments might be needed no matter how precise the presetting equipment.
The Big Picture
Maybe so, but the fact remains that a presetter’s extreme accuracy eliminates at least one variable from the machine setup equation. Haimer’s VIO series of linear presetters, for example, promise repeatability of ±2 μm (± 0.00008″), close enough to perfect that many parts can be cut to size on the first attempt, no matter how tired the CNC.
Yet Holden and others argue that accuracy is only one piece of the presetting puzzle. Because tool offsets can and should be transferred from presetter to machine control automatically, there’s no longer the risk of fat-fingering a decimal point like there is with manual toolsetting methods. Catastrophe averted.
Better process control is also possible when all tools are preset in the same manner, leading to more predictable part quality. And for those using a shrink-fit or balanced toolholder, Haimer is one of several companies that offer presetting combo units, saving valuable time in the tool crib.
“When a shop sees inconsistencies in its machining processes, many times it’s due to an unbalanced tool assembly or an improperly set tool,” Holden said. “By combining these functions in the same machine, it becomes that much easier to attain consistency from tool to tool. It also opens the doors to some pretty neat Industry 4.0 possibilities.”
Holden is referring to Haimer’s collaboration with process control solution provider Caron Engineering (Wells, ME). The two companies have developed an integrated system that reads and writes data to a toolholder-mounted RFID chip. If the machine tool is so equipped, this provides automated confirmation that the toolholder assembly is balanced to whatever rpm has been specified in the program—if not, the machine control either stops, sends an alert or adjusts the machining parameters accordingly.
“We can send data in two directions, giving users the ability to answer some important questions,” Holden said. “How long was that tool in the machine? How many times does it need to be changed each day? How fast was it running when it was in the machine? These are just a few examples of information that was previously quite difficult to gather.”
Industry 4.0 wizardry aside, shop floor efficiency is perhaps the biggest benefit of offline presetting. Whether you invest in a manual or fully automated system, presetting allows you to measure tools very quickly, and do so while the machine tool is busy making parts, Holden explained. “You’re reducing setup times, in-process tool changes are similarly shortened, and toolsetting is now a risk-free activity.”
That all sounds great, but where do you begin? Four presetter providers were interviewed for this article, and while they represent a major portion of the available technology, each has multiple platforms and options to choose from, ranging from bare bones units costing a few thousand dollars to fully automated systems with integrated tool management software. Because of this seemingly endless range of presetting options, those charged with selecting a system might decide to only dip their toes in the presetting water and leave the big decisions for later.
That’s probably a bad idea, noted Andrew Esposito, OEM sales manager at Koma Precision Inc. (East Windsor, CT). “While it’s very tempting to buy a presetter for the ‘right now,’ it’s important to look down the road,” he said. “Considering the speed at which technology changes, shops should choose a system that allows them to expand later on. I recommend starting with your must-haves, and think about where your manufacturing processes will be two to five years in the future. Plan your purchase to accommodate those improvements and advancements.”
One example of this was unveiled at this year’s IMTS, when Koma Precision introduced its new lineup of offline tool presetters. Esposito said they are aimed at increasing a shop’s current production capacity with semi-automatic measuring and advanced tool inspection features, but at an affordable cost.
Higher-end units offering the latest Industry 4.0 functions were also on display, as well as new software that offers an affordable way to transfer offsets to and from machine tools. “This goes well beyond the simple post-processing methods used in most shops and helps manufacturers close the loop in their tool offset data management,” he said.
Esposito pointed out three major benefits of offline tool presetting: increased tool life, decreased scrap rate and reduced setup time. The first might seem less obvious at first glance, but because presetters make it easy to verify cutter concentricity and eliminate runout, tools last upwards of 15% longer while part surface finish improves. Presetters also provide a great way to inspect incoming tools, a step that many shops overlook.
As alluded to earlier, accurate tool offset data helps reduce scrapped parts and the possibility of machine crashes, but it’s clear that the biggest improvement is increased spindle runtime. “With machine utilization rates averaging around 50% or less, most shops enjoy an increase of at least 25% with an offline tool presetter,” Esposito said.
Presetter Tech Smiles On
Zoller Inc. (Ann Arbor, MI), is another presetter and inspection machine manufacturer and tool management solutions company that presented new wares at IMTS 2018. Among other advancements, the company redesigned its smile« and »venturion« lines to make them more capable and user-friendly, and both were on display at Zoller’s booth.
“The handle that moves the optics carrier is more ergonomic, and we’ve added an »eQ« button to it which brings yhe optic carrier into position quickly and easily on both axes with the push of a button,” said Michael Kroodsma, marketing specialist. “And our »smileCompact« is a brand new, tabletop machine designed for entry-level users that is already quite popular.”
Zoller’s tool management software (TMS) was also a big hit. Matt Brothers, Industry 4.0 Technology Center manager for Zoller, said manual systems such as the »smileCompact« are an excellent starting point for many shops, but noted that the true benefits of presetting technology begin with
a comprehensive strategy that extends well beyond the mechanics of tool length and diameter measurement.
Measuring Tool Life
“Tooling costs are significantly reduced when you’re able to pick up any tool in the shop and know where it’s been, how long it was used, and where it’s going next,” Brothers said. TMS also allows you to assign cutting tools and toolholders to a machine or operator. Assuming you have the appropriate tool storage system, you can tie them to a specific cabinet, a specific drawer or compartment within that cabinet, and control when and who checks them in and out.
“There are all kinds of controls we can bring to the shop floor, and when you compare that to having people walking around for hours each day looking for tools or the machine downtime that comes when a tool is missing, investment in these systems is very easy to justify,” he added.
This is one reason why presetter buyers should take a hard look at the software that accompanies most systems. Functions such as CAD file import are available, which simplifies the creation of tool assembly inspection routines. Centralized tool management capabilities help eliminate the islands of tool information common in many shops. Integration to machine controls and CAD systems speeds the transmission of accurate tool data. Visibility to procurement data, historical usage, inventory levels and locations is assured.
As Koma’s Esposito noted earlier, it’s critical that shops take a long term view of their manufacturing operations before investing in a presetting system, and this includes the software. Said Brothers, “I always recommend that you gain a thorough understanding of your pain points early on. There’s a high likelihood that even a basic presetter will help eliminate many of those problems, but you shouldn’t underestimate the power of tool management software. Properly implemented, it’s a game changer for a lot of shops.”
Making it Automatic
Patrick Cratty agreed. The assistant product manager for TMS at BIG Kaiser Precision Tooling Inc., Hoffman Estates, IL, he’s encountered situations where a customer calls six months after purchasing a basic version of the company’s Speroni presetters, looking for more capabilities. “Once they see the benefits of presetting, it opens their eyes to other possibilities,” he said.
One of these is automation, something that many presetter buyers might consider overkill. Yet Cratty pointed out that CNC presetters make sense in a number of situations, even for smaller shops. Face mills with dozens of inserts, complex cutter geometries, inspection and documentation of large numbers of tools or tool features—these are just a few of the reasons why a manufacturer might opt for an automated system.
“If you’re only going to measure gauge length and runout, you can do that pretty darn quickly on even a basic presetter,” Cratty said. “But let’s say you have a form cutter and need to verify 25 different features—that’s where a CNC really shines. An operator doesn’t have to sit there moving the camera to every point. They can just put the tool in the presetter, hit start, and walk away. While they’re busy doing something else, the machine measures everything and determines whether the tool should pass or fail based on your inspection criteria.”
Automated machines are also more likely to sport high-end features like TMS software and RFID tagging, which everyone agrees is an excellent way to monitor and therefore improve on tool life. It’s also a great way to avoid costly mistakes. Because you can program the machine to read the RFID chip, determine how much life remains, and send a message to the operator that it’s time for a replacement, there’s no chance of loading a questionable tool in the machine—without an advanced presetter, these kinds of decisions are left to error-prone humans.
Whichever road you take, Cratty suggested that machine construction is every bit as important as its functionality. Look for a “shop-floor ready” presetter that’s built like any other machine tool, he said, with a cast iron base to minimize thermal growth, and hardened steel components to minimize wear.
“Speroni mechanically aligns and calibrates the machine’s axes rather than digitally compensating for errors in the control,” he said. “We’ve found that this level of mechanical calibration leads to significantly longer presetter life. When you consider that we have many units that are 30 years old and still being used in production, it’s a testament to this type of construction.”
Offline tool presetting offers significant improvements in machine tool productivity, but what happens once the cutting tool is in the machine? As mentioned at the beginning of this article, cutter deflection and machine tool inaccuracies cause “as set” tool dimensions to change once the chips begin to fly. And without a way to measure in-process tool wear, even the most presetter-savvy shop will find itself facing unpleasant surprises.
Dan Skulan, general manager of industrial metrology at Renishaw Inc., (West Dundee, IL), said machine tool probing systems take over where offline presetters leave off.
“With manufacturing tolerances being compressed, there is a requirement to fine-tune cutting tools once they’re actually in the machine,” he said. “It’s quite possible, for instance, to experience variation of 50 μm (0.002″) from the fit of a CAT 50 holder from one machine spindle to the next. Variation such as this must be dialed in on each individual machine, something that’s historically been done by the operator.”
Probing systems eliminate this effort, he said. They communicate directly with the machine tool control—all updates for tool length, diameter, and wear are automatically loaded using an internal macro function. Programming can be done using simple operator interfaces like Renishaw’s “Set and Inspect” application that operates on the control as well as on mobile devices. Once this data is in the control, it is easily sent through the network to external tool management databases via MTConnect or other communication protocols.
In addition, on-machine reporting functions allow shop floor personnel to monitor tooling-related processes directly.
As with presetters, probing options abound. Sharad Mundra, Mida probing product manager at Marposs Corp., (Auburn Hills, MI), said traditional turret, table, and spindle-mounted probes are available, as well as newer optical systems able to measure tools down to 50 µm (0.002″) in diameter. “This last one is our VPS camera probe,” he explained. “It’s like having a miniature version of a Zoller or comparable presetter in your mill or lathe.”
So capable have these systems become that budget-conscious shops might opt to delay the purchase of an offline presetting system in favor of in-machine probing. Measurement accuracy is whatever the machine tool is capable of. Setting a tool takes as little as 10-15 seconds. Cutters can be checked for wear and offsets made or replacement tools called for, all automatically. Broken tools are easily detected, eliminating the potential destruction of every tool in the carousel after blowing up a tap.
And compared to the probes of yesteryear, where complex macro programming skills were a must, operating one of today’s probing systems is as simple as calling up the appropriate app, entering a few values, and pushing cycle start.
Best of all, implementing such a system may be as easy as contacting your local machine tool distributor. “Haas sold 14,000 machines last year, and roughly 9,000 of them came with probes,” Mundra said. “Most every machine builder today has a probing system of some kind on its option list. If not, call us. In-process probing offers substantial benefits, even if you do have an offline presetter. Choosing one really comes down to your needs and your budget, but there’s little you can’t measure.”