Training CNC Operators

Include specific instruction that targets entry-level workers.

Columns From: 11/22/2013 Modern Machine Shop,

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Mike Lynch

Mike Lynch

I’ve often said there are two ways to improve a person’s productivity: You can simplify the required tasks so they are easier/faster to perform, and you can provide training that will increase the person’s proficiency. Either way, you should see a boost in productivity, since simple tasks and proficient people enhance output. This article will address training issues that target specific tasks.

Who needs training?
From a sheer numbers standpoint, companies tend to have the most trouble keeping CNC operator positions filled. A company that has 10 CNC machines and runs two shifts, for example, may need only one or two programmers and two or three setup people, but it could need as many as 20 CNC operators if it uses one operator to run each machine. Many workers coming into our industry have limited shop experience, let alone CNC experience, but companies tend to have entry-level workers start as CNC operators, so the most training should be targeted to these workers.

That is not to say that experienced employees, including programmers and setup workers, couldn’t benefit from training, especially if they are self-taught. Indeed, their work tends to affect others, and poor techniques and bad habits can have a devastating effect on productivity. But our focus here will be on training entry-level CNC operators.

What content is required?
The content you include in your training program must be appropriate to your situation in at least three ways: First, it must be in line with the student’s current experience and aptitude level. Second, it must address the specific tasks you expect them to perform once training is completed. Third, it must incorporate an effective presentation method.

Since we’re talking about entry-level CNC operators who have little or no previous shop experience, content should begin with some preparatory topics. In this module, I recommend covering some general machining practice topics, including shop safety, shop math, blueprint reading, tolerance interpretation and measuring devices. Follow up with more specific machining practice topics that are related to the actual machines they will be running, including an introduction to the operations the machine can perform as well as the cutting tools that perform those operations.

With a general understanding of basic machining practices, students then will be ready for more specific CNC-related topics. The next module can introduce students to the specific machine they will be running. Topics I recommed include machine components, axes, machine-specific features and functions (spindle, toolchanger, pallet changer, and more.), commonly used buttons and switches, and step-by-step procedures to accomplish specific tasks.

In module three, I would introduce machine-specific compensation types. With machining centers, for example, applicable topics will include fixture offsets, tool-length compensation and cutter radius compensation. With turning centers, topics should include geometry offsets, wear offsets and tool nose radius compensation. It will be during these sessions that students will learn how to assign program zero, assemble cutting tools (at least attaching the cutting portion of the tool), determine and enter cutting tool-related offsets (like those required for tool-length 
compensation on machining centers), and how to trial machine and make sizing adjustments with offsets.

In the last module, I recommend discussing tasks related to completing a production run. Topics can be presented in the approximate order that production runs are completed and can include workpiece loading/unloading, making sizing adjustments, replacing dull tools, and cleaning and deburring workpieces. You can also include company-specific topics like how to collect/record/report statistical process control data.

How will the content be delivered?
You have two options here: live, instructor-led training and self-paced training. Each method has its pros and cons. Most students prefer instructor-led training because they can get questions answered right away, however, this can be tough to justify if there are only a few people to be trained. Note that the time required to present the class is but a small portion of the overall time required of the instructor to develop, learn and practice with the content, not to mention the time required to develop practice exercises and complete the grading once the class is started.

With self-paced training, if you’re using materials provided by an outside source, you lose some control of the content, meaning you may have to provide additional content of your own. Also, someone who understands the content should also be involved in the training to act as the facilitator for the class. This person must, at the very least, meet regularly with students to go over the content and answer questions.

Evaluating Effectiveness
Once implemented, it is important to maintain the class. Do students possess the skills you expect once they have completed the class? Were there common questions from all or most students that indicate areas in need of improvement? You must strive to improve content and delivery methods to make your classes as effective as possible.

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