Automating Complete Workholding Changeovers for Turning

Quick-change workholding devices for CNC turning centers have been around for a while. For example, Hainbuch, manufacturer of clamping, measuring and automation solutions for milling, turning and grinding equipment, offers manual, microns-repeatable quick-change devices such as its hex-style Toplus for OD part clamping and Centrex for ID mandrel clamping.

That said, the company recently has made strides to remove the human element from changeovers altogether, believing that it represents a natural, automated next step for the use of these types of workholding devices to support appropriate production needs.

The concept Hainbuch developed, which the company calls its Automated Change (AC) line, uses a robot (brand doesn’t matter) to change all workholding elements for a given job automatically to enable long stretches of reliable unattended or lights-out operation, even when batch sizes are small. (It’s similarly a natural next step for robots that, for many years in the machining world, have been used to simply load and unload material and parts into and out of machine tools.)

I was introduced to the AC line during an unveiling of a demo cell in the company’s IMTS 2024 booth. During the gathering, Timothy Wachs, Hainbuch America Corp. president, reiterated that installing a robot in front of a machine tool to load and unload material and completed workpieces is nothing new. But, he said the ability to use a robot to change out all workholding elements — such as clamping heads, end-stops and entire clamping devices, including three-jaw chucks, OD chucks and ID mandrels for a variety of different parts, all without human intervention — is new to the industry.

As shown in these photos taken at IMTS 2024, a basic version of such a machining cell would include a turning center or perhaps multispindle machine, robot, storage locations for interchangeable robot end effectors/grippers for workholding elements and parts, material storage areas and so on. In a real-world application, all of this would be customized per an end user’s needs.

Basic questions that arise, however, include “When does this type of advanced automation investment make sense?” and “How does a shop determine this and design for it?”

To that end, I spoke with Edwin Bayer, engineering manager for Hainbuch America Corp., who says initial discussions between a potential end user and Hainbuch’s application engineering team is a very important first step to determine if the AC line concept is appropriate to support the end user’s needs. After all, it’s possible that a shop is better served continuing with its existing manual workholding changeover processes, which Hainbuch would point out be that the case. That said, this type of robotic automation next-step might make sense for others. In fact, the company already has AC line installations at a handful of manufacturers in North America, primarily for aerospace and medical work.

Those AC line installations involved manufacturers that were already using Hainbuch manual quick-change devices, but were looking to elevate that concept to the next level in terms of automation. And of those installed AC line cells in North America, most have been designed to accommodate relatively small batch sizes — approximately 50 to 100 part types/sizes on a single machine running lights-out. Typically, the automated cells were designed around parts the customers had been producing for five to 10 years and plan to continue manufacturing for years to come.

Bayer says this situation — existing jobs that are likely to continue — can be a good way to justify the investment in an automated AC line. And, in some cases, the manufacturer might already have a robot being used for part loading and unloading that could then be re-programmed and tooled to work in an AC line cell.

However, the AC line concept provides the flexibility to add new jobs to a cell, too. This generally doesn’t require much outside of space for different workholding elements for the new parts because the machine is already prepped for automated worhkolding changeovers (the AC flange is already attached to the spindle, for example). There’s really no changes required in terms of the machine, Bayer notes.

For shops considering the AC line concept, Bayer explains that it is important to determine how many parts the cell should accommodate, how many operations will be performed, the number of machines and robots in the cell, available floor space for the cell and what the ultimate goal of the cell is.

Then, discussions must dive deeper into the machine(s) itself. Integration is simpler with new machines that can be built to suit the needs of the AC line. Older machines might have to be retrofitted with components such as automatic door openers, for example.

Bayer notes that it’s also important to consider, and maintain, equipment cleanliness, which is something that shops new to robotic automation/unattended machining sometimes overlook. Measures must be put in place in place to keep important component contact areas clean, to use coolant to flush away chips and so on. It’s counterproductive to have to stop production to blow out chips or perform some other similar manual activity. And therein lies advantages of the hex design of Hainbuch’s Toplus (for OD clamping) and Maxxos (for ID mandrel clamping), he says, that have sealing features built in to prevent chips and particles from getting inside the devices.

If the choice is made to move forward with the AC line, an automation integrator is brought in. Hainbuch America Corp. has formed relationships with a couple trusted companies in North America, but the end user is certainly able to bring in a different integrator it knows and perhaps has successfully worked with in the past.

Ultimately, Bayer says that the goal with a concept such as AC line is not to reduce a company’s personnel headcount. Rather, it’s to leverage that technology to redeploy those people to more valued duties. One example would be for them to focus on prototyping work for new jobs and establishing predictable, effective machining processes for them. After that, the shop can consider how best to optimize those processes by applying automation.