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Reader Question: We expect to see a lot of growth this year, but are currently struggling to lock down key process decisions from job to job that create inconsistency. How do you recommend standardizing programming/setup techniques for a shop that is growing fast?

Miller’s Answer:

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As the manufacturing industry continues down the path of reshoring —potentially accelerated by recent news and events — all shops are going to be pushed to grow and hire more. Rarely do new hires perfectly match your shop’s approach, so standards and a solid reason “why” are important to bring them into the fold quickly. This applies to young hires who need to develop their habits and even experienced hires who may have some habits from previous jobs. In fact, the habits might not even be that bad, they are just different from how your shop operates. Programming standardization is a great way to get the shop on the same page to eliminate mistakes and streamline communication across people or departments.

The Approach

I’ve been lucky in my career to trial a lot of different machinery and controller types. I can say I’ve run all the household names and all the major controller types that they come with. That’s not to say I know them all as well as some of you do, but that experience did teach me a big lesson: All CNC operations boil down to how you handle tool offsets, work offsets and programs. Meaning, all you need to get a rudimentary program going on any machine is to tell it how long the tools are, where the work piece is and to upload a safely formatted program. The rest is a matter of preference and performance.

How this applies to your shop: No matter how many machine brands or types you have, there are three categories that apply broadly to build your programming standardization. If you are a shop with primarily one or two machine types, then you can push this standard down one level further into how, why and when you may use specific machine functions as well.

Tool Offsets

The first decision I would make is how the shop is going to handle tool offsets. For tool length, some will be easy to decide, like flat end mills or boring bars, in which you will probably elect to always set the length to the end. However, tools like ballnose end mills might be set to full length or center of the ball (tool tip minus ball radius). Drills can be set to tool tip or full diameter depending on how you want to program drill depths. Tools that can cut on both sides like T-slot tools could be programmed to the front or back and need to be offset accordingly. As you may tell, all of these require a decision so that programmer, setup, tool crib and so on are all standardized to the same thing.

The second part of this decision may also depend on what’s easiest during setup. For example, a presetter may not be available, so it will be easiest to set all tools to their full length at the center of the tool in the machine. Another example is a contact tool setter, which cannot measure a drill’s length at the full diameter, but an offline presetter can. Very complex form tools may not have a good edge to preset in the machine, so using an indicator or touching off the table is the only viable option. Therefore, it’s worth it to standardize based on the resources available and how you envision programming your most common part features.

Work Offsets

The next decision point is where to set the work offsets on a consistent basis. Options here are endless, but some common strategies exist. First is the part itself. The center of the billet in op. 1 is common, while op. 2 may be a critical datum or the intersection of the A, B and C datums. Another is to choose a fixed asset in the machine, such as the hard jaw on a vise or the center point of a zero-point system. Another option might be ensuring the center of the rotary axes stacked on the table — meaning any riser, vises and so on — are just compensated for via the program.

All these options are valid, but should also be decided among the broader view of the shop’s operations. How often does workholding move in and out the machine? Is it critical that program coordinates to match the drawing coordinates for cases where accountability is key?

Programming

When it comes to program standardization, it should first be done with respect to how the tools offsets and work offsets were standardized. This is just a baseline to anchor the process and reduce “special cases” or odd instructions that could follow each job and create problems between programmers and those doing setups.

Secondly, while all controller types do take somewhat different code — sometimes very different — this is where working with your CAM supplier on the postprocessors will become key. I believe, as a baseline, all programs should have safe start blocks at the beginning of every tool so that processes can pick up seamlessly from any tool. They should also be well documented with good headers and a note of each tool. These simple procedures will make sure those at the machine know when the programs where made, and that they reflect the job they were meant for and can be operated with proper understanding of what is going to happen. From here, your shop can introduce other standards like when and how coolant codes are used and when to implement special machine functions, as well as develop procedures for safely recovering a process from failure, such as a broken tool.

While standardizing multiple employees who run multiple machines and balance multiple jobs a day can feel daunting, keep it simple and start with tool offsets, work offsets and programs. At the very least, you are streamlining setups and reducing the risk for errors like wrecks. From here, you can refine this process as the shops begins to embrace the standard and offers clever ideas of their own to implement further standards that safeguard operations. Before you know it, the “standard” will just become “how we’ve always done it.”

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 .