At the start of early childhood, we learn the importance of safety. From taking the time to buckle your seat belt to following the appropriate safety precautions during a fire drill, we acknowledge that even though we may not want to make these steps, they are still necessary. Preparing and practicing such steps allows for safety to become routine. That means that when something does go wrong, you are well prepped and ready for action. Safety is a guiding principle throughout our entire lifetimes. As we reach adulthood, we continue to prepare for the unexpected. Proper safety precautions become especially important when operating dangerous equipment like CNC machines. Whether you are a beginner or a skilled operator, taking precautionary actions is crucial.
Computer-Generated or Manually Programmed: Precaution is Always Necessary
Dealing with industrial equipment can put operators into dangerous situations. Whether you are a novice or a seasoned machinist, precautionary steps are critical to a safe and successful experience. Manually programmed machinery often has complications. A misplaced keystroke or inaccurate digit may cause an error. Even a small error of this nature can cause an entire job to be scrapped and put the operator at risk of injury, making safety measures that much more critical to the machining process.
Flaws may even be found in computer-aided manufacturing (CAM) systems. Although they are more likely to be correctly constructed, issues like incorrect feed, speed, or
The Top Three Priorities
Working with any CNC machinery requires safety measures. No matter how much experience an individual has acquired, there is never a point where one “outgrows” precautionary steps. These safety tips can be divided into three levels.
- The Operator – Even if the person operating the machine is an experienced professional, safety precautions are still necessary. It is common for an individual to cut out safety steps because they feel that their skill and experience will compensate. Despite this appeal to efficiency, the increased risk is not justified by the saved time.
- Machine Tools – CNC equipment is expensive and often difficult to replace. Taking the proper preventative measures can prevent the expenses that accompany new parts or buying an entirely new machine. Repairs and machine replacement along with lost productivity can create a large price tag. Well planned safety protocols protect the machinery as well as the operator.
- The Workpiece – Depending on the materials used, incorrectly machining pieces can become extremely costly. Expenses may range from ten cents per piece to several hundred dollars of scrapped material. For this reason, the company must ensure that their operators are taking the essential safety steps to prevent extensive loss of profits and guarantee the workpieces are correctly made at the appropriate size during the first production run.
The Steps that Save
To avoid some typical mistakes that come with CNC machining, the following steps should be taken to verify programs:
Recognizing Flaws in Syntax
If your CNC machine has a switch labeled machine lock, this procedure can be used to scan the entered program for syntax mistakes. When the program is setup up, the
Identifying Motion Issues
After the syntax of the program is approved, the motion of the program is tested. Particular care is required by the operator, especially since there is no workpiece in place. To complete this procedure the operator must:
- Turn off the machine lock switch
- Decrease the dry run motion rate as much as possible
- Put the rapid override switch to its lowest setting
- Be ready to press the feed hold button
The motion of the program is studied by the operator to ensure it flows correctly. From there the jog feed rate can be adjusted to a comfortable speed. If there seems to be a flaw the operator can stop the cycle by pressing the feed hold button and then the reset key. After stopping the cycle, the operator goes back and makes the necessary adjustments.
In addition to examining the machine for serious motion issues, the operator should also check for proper spindle rotation and other necessary program motions. In order to ensure there is an accurate evaluation, this process should be run several times to allow the operator to catch all major and minor issues.
Confirmation of Drill Motions
The operator should complete a cycle with the dry run switch off, without using a workpiece. In the prior procedure, the operator was able to take control of the motion rates with the dry run motion rate switch. However, with this switch on, the operator is not able to spot the difference between rapid motions and cutting motions. This can cause issues like drills working at rapid where they shouldn’t be, potentially causing a broken drill or even an injury. By completing this final check of the cycle without a workpiece, the operator can ensure the drill is
Applying the First Workpiece
Optimizing the Process
After the first product of the machining process is complete, the process needs to be optimized. Optimization allows for maximum efficiency during the production period. We recommend that the machine does not rapid for the first few pieces to enable the operator to get comfortable with the cycle before speeding it up. This precaution allows the operator to evaluate the process more efficiently and minimizes the cycle time where it is optimal. If there are any significant program changes, we advise that you go through the verification process again.
Learning to Expect the Unexpected
Despite what may seem like a lengthy list of procedures, going through the verification process for each of your programs allows you to maximize efficiency. The verification process protects the safety of machinists and prevents unnecessary wear and damage to the machinery saving money in the production process. As with any safety precaution, it is meant to assist you in situations when the unexpected occurs. When it comes to safety, there is no time limit!
Sources
https://www.mmsonline.com/articles/key-cnc-concept-10verifying-cnc-programs-safely
