Automation is finally at the forefront of CNC manufacturing trends. Lack of labor is the main driver for automation today. For years, the justification for automation was almost always based entirely on financial return. Post-Covid, not only has labor become more expensive, but it may also not be available at all. For many CNC manufacturers, automation is no longer a strategy to improve profitability, it is becoming a strategy for survival.
I’ve spent nearly a decade focused on automating high-mix CNC manufacturing. My automation journey started with my own CNC machine shop. Beginning with a vision and a lot of optimism, we went from a single automation system that was “failing to meet expectations” to automating more than 20 CNCs in our own shop. We ultimately integrated more than 1,000 unique parts into our automation systems.
From that start, we built VersaBuilt into a company dedicated to helping customers integrate automation into high-mix CNC manufacturing. While most other companies have focused on high-volume automation, we have remained focused on high-mix. Why? Because we built the technology needed to successfully automate high-mix and high-mix represents the largest segment of the CNC market.
What we gained over the years is a lot of valuable insight into what it takes to make automation work in high-mix CNC manufacturing and what often leads to failure. In this post, we’ll look at the top 5 mistakes we’ve seen companies make in their journeys to automating CNC manufacturing. Hopefully, you can find some valuable insight from some of the graduates and dropouts of the High-Mix CNC Automation School of Hard Knocks.
#5 Automation is only for my High-Volume Parts
Most customers have outdated ideas about how “hard” or “expensive” it is to automate CNC production and how “long” it takes to change-over automation. Many CNC machine shops believe that automation is too difficult for anything but their highest volume parts. Automation certainly works well on the high-volume parts but automation can work equally well on low-volume parts.
The arguments against automating low-volume parts typically come down to the time and cost to integrate a part into the automation system and the additional time it takes to change-over the automation system to the next part. VersaBuilt’s automation systems are different from other automation systems in these two key measurements.
After some training and experience, moving an existing, operator-tended CNC part to a fully automated process will typically take about a day. Less for simple parts, more for complex parts. When adding an all-new part to the CNC, the additional time to integrate with the VersaBuilt automation system is typically less than a couple of hours. Again, more for complex parts, less for simple parts. Part change-over with a VersaBuilt automation system typically takes less than 15 minutes.
What I like to tell people is this: if you’re going to make a part in batches of 5 or more and you’re going to run more than a couple of batches over the life of the part, it is probably worth automating.
#4 Making “Lights-Out” Production your #1 Objective
Many automation inquiries coming into VersaBuilt start something like this…
“I think I can justify this automation purchase if I can run all my high-volume parts on nights and weekends. I want to push this automation thing to the side during the day to run my lower volume stuff and then set up at the end of the day for the high-volume robot stuff. I need this thing to be able to run from Friday at 5 pm until Monday morning at 7:30 am. Can it run that long?”
I’ve seen many customers struggle to try to get their automation to consistently run overnight or over the weekend. Often I see the time and effort in long unattended production is time and effort poorly spent. Getting long unattended run times can be a lot of work. And contrary to what many might assume, the automation process is not the hard part. The CNC process is the hard part.
Every part and every CNC machine are different. Parts that produce a lot of chips cause problems. Parts that wear cutting tools quickly cause problems. CNC machines with poor chip handling cause problems. CNC processes that are not already well controlled with tool life management and in-process inspection, cause problems.
If it takes 1 unit of effort to get a CNC process to reliably run for 4 hours unattended, getting that same process may take 10x to 100x that effort to run reliably for 48 hours. Again, some parts and some CNC machines make long unattended run times easier than others. In most cases, you will get more return on your investment (and more production output) putting in the effort to get 10 different part numbers to run reliably for 4 hours unattended vs 1 part number to run reliably for 48 hours unattended.
Tweaking your production shifts may help. Before automation, swing and graveyard shifts were always a problem. I gave up on them and bought more equipment. Automation changed that. By keeping the swing and graveyard shifts focused primarily on keeping machines loaded and monitoring the production process, we were able to run much smaller crews at night that could easily maintain high levels of productivity.
#3 Starting your Automation Journey with your “Problem Part” or “Problem Machine”
We sometimes get inquiries from customers that are desperate for a solution. They’re falling behind and they can’t find the help they need. They believe if they can get this one problem part or problem machine they are most behind on automated, they can at least catch their breath.
We always want to help and provide the most impact for your business in the shortest amount of time. But starting with something that is already a problem and adding something new may not be the fastest way to bring relief. Why? Automation doesn’t always go smoothly. Adding automation to a CNC machine will bring it down for at least a day or two. Developing your first automation process will take another day or two. Getting the automation process and the CNC process working smoothly may take another week or two. High levels of urgency and a new automation process don’t always go well together.
Every case is different. Part of our job is to listen to your concerns, understand your situation and then advise you on the course of action that will provide the most pain relief in the shortest amount of time.
We may advise bringing in a new CNC machine so that the old process can run while the new process is being brought up. Or we may suggest that you automate another machine that isn’t in the critical path to free up some labor to get the problem machine caught up. Sometimes we can even offer to “turn-key” your process in our facility on our CNC machines, providing some finished product to meet your backlog and ensuring that the process will hit the ground running on your shop floor.
#2 Trying to Force a new Automation Process onto a Legacy CNC Process
Although we sell automation systems designed for the average machine shop to perform their own part integration, we are frequently involved in helping customers perform part integrations into their VersaBuilt automation system. Many times, we are helping customers integrate legacy parts that have been made the same way for 5, 10, or even 20 years or more.
We always encourage machine shops to leverage what works but only where it makes sense. Often existing CNC programs can be used just by updating the fixture offset for the new workholding. For CNC milling, adding automation is almost always going to require going from a manually actuated fixture, like a Kurt vise, to an automatically actuated fixture, like our MultiGrip vise. Although we can sometimes leverage existing fixturing, often, it ends up creating more work and more failures than just cutting a fresh set of soft jaws on the new automation workholding.
Another thing we frequently encounter is legacy CNC processes that could be completed in two ops on a single machine but are currently three or more operations on one, two, or even three CNC machines. Many times, these processes were developed at a time when 4 or 5-axis machines were not practical, or it was assumed that running the part across multiple machines would achieve greater production output.
When it comes to automating high-mix, make one-and-done your goal. That is, whenever possible create automation/CNC processes that allow a part to be completed in a single CNC machine. It may not always be an option for your circumstances, but it is almost always your best bet when it is an option.
#1 Optimizing the CNC machine at the expense of the CNC operator
If you’ve been around CNC manufacturing very long, you’ve probably had it beaten into your head, “we need more production out of that machine!” Optimizing the CNC process to squeeze more production out of each CNC machine is a worthy objective… until the optimization of the CNC process interferes with the optimization of the CNC operator. Automation, and especially high-mix CNC automation, may require small trade-offs in the efficiency of the CNC process to the benefit of CNC operator efficiency.
Let me give you an example. An existing CNC process has the operator load four parts in the CNC table at once; two first ops and two-second ops. The CNC cycle time is 30 minutes and produces 2 completed parts each cycle. VersaBuilt proposes processing one part at a time, through two operations, the CNC cycle time for both ops will be 18 minutes, and the time the robot spends transferring parts will be 2 minutes per part. (The CNC cycle time is longer per part because the CNC can’t share tool changes across multiple parts).
The machine shop owner is outraged, “I can’t afford to go from 4 parts per hour to 3 parts per hour, I’m already way too far behind!” This is where things get tricky and we have “some explaining to do”. The machine shop owner is not getting 4 parts per hour. Many CNC shops fail to account for the amount of time an operator takes to tend a CNC process and the time the CNC machine sits before the operator tends it. Well-run shops, with a high ratio of CNC operators to CNC machines, will struggle to get above 50% spindle cycle time over a shift. Automated systems are generally between 80% and 90% spindle cycle time per shift. An automation system will almost always outperform an operator-tended system. And that’s before we talk about unattended production.
Automation is first and foremost a tool to make your CNC operators more productive. Keep telling yourself that over and over again.