Published 08/08/2025

Refining the Handoff Between the CAM Program and the Real-World Process

Despite the best intentions in the virtual world, the manufacturing process is limited to what survives the handoff from screen to spindle.

• Software
• CAD/CAM

Reader’s Question: We’ve invested in better CAM and simulation software. We’re getting work to our machines faster than ever, but things seem to fall apart there. Details are missing, which has caused scrap parts — and even one crash. What are we missing in translation from virtual to actual?

Modern CAM has given us impressive tools to execute more work faster than ever with tool paths that suit virtually any problem you may face. And it’s about to get a lot faster with more AI-assisted enablers coming down the pipeline. However, we must recognize that our jobs are still quite physical in nature in that real tools are colliding with real metal and we’re always responsible for parts that measure good in the real world, not the virtual one.

This is where I think we must recognize something important: CAM is not the machining process. The machining process is everything from the programming, the postprocessor, the machine itself, the surrounding gear and how we’re setting up and utilizing all these components. Therefore, the process isn’t just what’s simulated in CAM, it’s the sum of the parts. Despite the best intentions in the virtual world, and the best equipment in the physical world, the process is limited to what survives the handoff from screen to spindle. That handoff is where most of the process lives, and where most of it can fall apart.

Good CAM doesn’t build a good process on its own. The process is how we translate a virtual idea into a physical outcome, across multiple people, setups and machines. That handoff requires a lot of structure, because what works in simulation can fall apart in execution if any small component is out of place. One broken tool, one fixture bolt a little loose or one unexpected episode of chatter can quickly ruin a high-stress prototype run or a large batch of unattended production.

Therefore, the totality of your machining process must include instructions for how setup is documented and transferred, how fixtures are described used, how probing is assigned, how offsets are mapped and how tool wear, machine limits and part risk are accounted for. It’s the totality, not just the cutting strategy developed in CAM.

Recognizing now that the process is the sum of all the small points of influence, here is what I would start looking at shoring up to ensure a smoother transition from virtual to physical.

First, your team needs to develop proper setup instructions for those at the machine. At first, it may be as simple as which specific vise to use, where and how to mount it to the table and whether or not it needs an edge locator. When building the tools, the tool type, stickout and toolholder should be documented, and the shop should at least have a baseline standard for acceptable overall length tolerance between CAM and actual, say ±0.04".

Offset management is a massive piece to the CAM handoff procedure that can’t be ignored. We always need to remember the machine is blind, and we must tell it, very precisely, where the workpiece is, and how long the tools are. The setup personnel should know exactly where the workpiece offsets are meant to be, and if there are multiple, they should know how many they need to find. They should also have instructions if an offset needs to be calculated from another point, as well as where to set the length of the tools and if there are special cases like form tools, measuring drills to the full diameter versus the tip or utilizing the center of a ball nose or spherical end mill versus the longest point (especially crucial in full five-axis motion).

Another area to consider is where you are building speed and feed assumptions and if those make sense once the physical setup is built. For those who utilize tool libraries in the CAM systems, were the speed and feed assumptions build from the catalog numbers or from experience? If they came from the catalog, then the baseline was built from a system where we may not know the rigidity compared to our own setup. If you build it internally, is the machine last tested compatible enough with the machine meant to run these speeds and feeds now? If you know you build speeds and feed on a CAT 50 platform, but are now running on a HSK40 spindle, you’d be in real trouble. Or perhaps more simply, if the new process requires longer tool setup than normal, was this accounted for?

One last area to consider — which isn’t quite as simple as matching the virtual to the physical — is doing a risk analysis of your planned process. However rudimentary, it is worth spending time not just building the tool paths, but making sure your plan can hit the specs. For example, there could be a stack up from op. 1 to op. 2 that needs special care and could benefit from a quick probing cycle. Or there could be surface finish risks in deep pockets where chips building up is never witnessed in CAM, and there for ignored until its too late.

Shops must recognize that the entire machining process includes everything from the first CAD spin to completed, in tolerance, physical part. Once your shop recognizes that CAM is part of the process, not the actual process, things will get better quick. With the time you’re saving in programming, I recommend you invest some of it refining the handoff between the virtual world and the real world for more consistent and safe results. Once this is nailed, then you can stress-test the system and absorb the full amount of work you think you can with your new capabilities. Before long, the process you’ve developed just becomes the norm and this will be a small chapter of struggle on the way to an efficient shop.

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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 mmsonline.com/MillersEdge.