How to Choose the Right Automation Solution for Your Shop

Reader Question:

We have been shopping automation solutions for a few of our machines to keep up with production. The company we’re working with has many options of robots, cobots, pallet systems and even robot-loading pallet systems. Can you help us differentiate these options and where we might use each?

Miller’s Answer:

Of all the advancements in our industry, I find the proliferation of automation to be one of the most interesting for shops. What used to be reserved for higher volume manufacturers, is now available in compact, flexible solutions that are adaptable to any platform or controller type.

Historically, what hasn’t changed in the space is our means to get work in front of spindles. Even when automation was reserved for only the highest volume manufacturers, you either had a transfer system, which shuttled a workpiece on a dedicated fixture to many process steps, or you had a robot, which tended to a machining center one part at a time. So, to keep this decision simpler for your shop, and frame future automation decisions, there are essentially only two types of automation solutions: workpiece handling and pallet handling.

Workpiece Handling vs. Pallet Handling

A workpiece-handling solution is one where the automation is taking the raw material and loading it directly into a common workholding device. This could be done through a robot arm, a gantry arm or even a bar feeder, while the machine side will have chuck, air vise or even a custom hydraulic or pneumatic solution to receive the material for processing.

A pallet-handling system shuttles the workholding — with the workpieces already loaded — to the machine through a common connection type. This is often accomplished through retention studs that firmly hold the pallet to the machine, with a very repeatable connection so work offsets are consistent from load to load.

A workpiece solution requires a little more attention to how the part is loaded, the logic between machine and robot and attention to chip control. However, something like a collaborative robot can be very flexible for a shop loading a mill on Monday and a lathe on a Tuesday. A pallet-handling solution can consume a lot of cost upfront due to the extra workholding in the same way you would need to fill a tool magazine on a new machine, but these pallets are then setup in perpetuity, available on-demand as they are needed.

There are distinct advantages to each type that make both appealing options for shops. To make the best decision, the broader shop picture should be considered. The goal is to find the payoff of set up time vs run time. For example, a robot may require some time to work out the motion and logic for each run, while a pallet system will require a lot of time finding work offsets for each incoming pallet but is a one-time activity. Each of these is time not cutting metal, so the productivity benefit to taking time away for these activities should be considered.

If the bulk of your work is longer runs that can be fed into a common workholding system, such as vises for Op1 and soft jaws for Op2, a workpiece-handling solution makes sense. You get the productivity of automation without the unnecessary expense of extra pallets and the workholding for them.

If your work is very diverse and runs are short, like a prototyping shop, a pallet system will make more sense. Setting up a robot in this instance may feel cumbersome for each run, but you can set up your most common workholding solutions once on a series of pallets, knowing that when you need them, they will repeat. The advantage here is virtually eliminating setup times for future projects.

Another thing to think about is what implementation your shop prefers. With modern solutions, a pallet system can do a single part cost effectively, and a workpiece handler can absorb some mix of parts efficiently, so even if one solution may be more ideal than another when focused on part and process, things like floorspace, ease of implementation and operator expertise, become equally valid decision points. Modern pallet systems have become very compact and are tightly integrated into the machine’s controller, which means the learning curve is very low. Modern robots can easily change grippers and are programmed in a simplistic way. Therefore, two shops with similar incoming work may come to two equally productive and profitable solutions in their own way.

The nice part about modern automation that I haven’t discussed yet is that none of it needs to be permanent. Meaning, a decision you make to satisfy today’s constraints can likely be refitted or redeployed for future needs. A workpiece solution can easily flex from machine to machine, and a pallet solution can solve the solution of high-volume or high-mix work with just workholding changes.

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Do you have a machining question? Ask the expert. John Miller leans on more than a decade of industry experience to answer machining questions from MMS readers. Submit your question online at www.mmsonline.com/zc/mms-millers-edge-column