The market for CNC automation equipment has exploded over the past 5 years. Price points have come down significantly. Cobots have created new automation possibilities including DIY automation. A discussion of all possibilities could take weeks to write and hours to read. I’m going to narrow this discussion down to automation equipment targeted at high-mix manufacturing of parts less than 20 pounds. Why? Because this is the largest segment of CNC manufacturing in North America and Europe and represents the biggest opportunity for increasing productivity with less labor.
What have we learned about improving high-mix CNC manufacturing over the decades? Reduce setup times. Single Minute Exchange of Dies (SMED) is a concept born in the 70s that has driven much of the progress related to high-mix CNC manufacturing. (Note that “Dies” in SMED is a dated term that refers to the workholding in the CNC that holds the part to be machined.)
Minimizing part change-over time is often the most important goal of high-mix CNC manufacturing. The same goal should apply to high-mix CNC automation: Single Minute Exchange of Automation Dies (SMEAD). In the case of high-mix CNC automation, we need to consider both the CNC and the automation system changeover time.
Pick Your Parts
One of the biggest mistakes I see shops make as they adopt automation is to design a custom system around a few of their higher volume parts. If you have a single part or family of parts that you’re confident will consume the capacity of one or more CNC machines for 5 to 10 years, then by all means optimize and customize an automation system around those parts. But that’s not high-mix, that’s high-volume. Any CNC that will be running different part numbers on a regular basis should use automation designed for high-mix: SMEAD.
A high-mix automation system should be as flexible as possible. Avoid infeed/outfeed designs, robot grippers, or CNC workholding that significantly limits the size or shape of parts that can be processed or requires significant change over time. If you process a lot of different parts, the time and cost to introduce a part to the automation process must also be considered. Will new parts require new robot programming? New robot grippers or gripper fingers? What about the infeed/outfeed?
You’re not likely to find an automation system that works optimally for all of your parts. You may find that 90% of your parts can work well with a particular automation system but 10% just won’t work or won’t work optimally. Don’t let the 10% of your parts drive you to a bad decision for the other 90% of your parts.
Standard vs Custom Automation
Up until the past 10 years or so, virtually all CNC automation systems were custom built to a customer’s particular needs. Custom systems were typically designed around a part or small family of parts and robot programming, grippers, and CNC workholding were typically done by a regional “robot system integrator”. Historically, almost all custom automation was targeted at high-volume applications. Reduced integration costs have allowed custom automation systems to venture into higher mix applications. Modern custom automation systems have become more flexible but adding new parts to a custom automation system is typically done by the robot system integrator with part changeover typically handled by the CNC machine shop.
A standard automation system is a pre-engineered, pre-programmed, and mass-produced (relatively speaking) system designed to be used as a tool by a typical machine shop. With a standard automation system, the CNC machine shop adds new parts to the automation system and performs job changeovers. A well-designed standard automation system should not require significantly more time or cost to add a new part to be automated than traditional operated-tending production. And any good automation system targeted at high-mix should not require more than 10 minutes to change over the CNC workholding and automation system between jobs.
In general, custom automation systems are for high-volume manufacturing and standard automation systems are for high-mix manufacturing. Can you imagine going to some local shop working out of an industrial park to custom build your next CNC machine? And depend on that shop every time you’ve got a new part for production? Of course not and why would you do that with your automation system?
As always, there are some exceptions to the rule. Most standard automation systems are built around widely used workholding strategies that fit a broad number of parts. Like vises and chucks. If most or all of your parts require a less commonly used CNC workholding, like vacuum fixturing, you may need to look at either a fully custom system or a semi-custom standard system. As automation continues to grow, you will see more types of standard automation systems that fill niche needs like vacuum fixturing of parts.
Next up: Part 3 – Continuous Improvement