CNC Machine Tool Mistakes – The Big Four

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From our experience, the bulk of the issues faced by machinists in using CNC lathes, milling machines and multi-axis machining centres revolve around four main issues.

#1 Utilising the Wrong Cutting Tools / Settings
Choosing the wrong cutting tool for the work may often bring about poor quality material finishes. This could be seen as rough edges, cutter marks on the surface, raised marks, or burn marks on the material's edges or corners. Extensive tool wear may derive from this error.Hit on Other Error Accuracy Calculations of CNC Machine Tools  to explore more about our services and sites. Hope you ll like our more services.

Poor material finishes could be because of either bluntness in the tool used, or improper feed speed ratio. It may also be caused by the wrong dimensions of the tool for the work at hand with regards to the sizes, quality or match with the material.

To eliminate this, it is essential to find the right tool and setting for the work and material.

#2 Errors in Programming
As highly sophisticated equipment controlled by CNC computers, a lot of the difficulties which arise in CNC machining often originates from programming. These may originate from a lack of understanding of different G and M codes useful for the controller, wrong set-up, or inputting the wrong data variables into the CNC controller.

To eliminate these errors, it is important for new operators to be adequately been trained in different ways by which CNC machines may be programmed. Comprehensive user manuals and training, motion sequencing, and operation of the machine ought to be provided to new operators by the machine suppliers or experienced operators on the shop floor.

#3 Poor Maintenance of CNC Machine Tool
Modern machines with multiple constantly moving mechanical parts, CNC Machine Tools must be regularly cleaned and maintained to help keep them running optimally.

Failure to clear away dirt, material and other debris could result in a build-up which as time passes can result in inaccuracies in machining or even machine failures.

To prevent this, it is a must for machine operators to follow along with an in depth maintenance regime for the machine tools in use. They should also regularly check quantities of coolants or airflow, e.g. air filters, to ensure that operations continue being smooth and uninterrupted.

Note: an overheated spindle could derive from having a choked air filter in your cooling system.

#4 Inadequate Worker Skill and Training
With increasing usage of computing and programming, CNC machine tool operators these days need a different pair of knowledge and skills. Without the proper organisational, planning and programming skills, workers are unable to optimize the yield of these machines even though they have machining skill and experience using previous models of machines in the past.

To ensure that is resolved, you'll need to hire the proper machine operators who can visualise and design the machining process, select the correct tools and sequences for the work, and write the programmes.

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Other Common CNC Machining Problems and Issues
Beyond the aforementioned areas, machine operators may also encounter the next problems using their CNC machines.

#5 Clamping/ Unclamping Problem of Chucks and Fixtures
This can be a major issue once the piece to be labored on cannot be securely gripped by the chuck, or when it shifts or vibrates throughout the machining process. To eliminate this, consider the next steps:

Check if the part is correctly positioned to ensure secured clamping.
Check if the hydraulic pump and the hydraulic pressure is adequately set-up.
Check if the jaws used are correctly set and adequate for gripping the material. Ensure a broader surface gripping instead of point gripping.

If the chuck doesn't open / close, check to see if the foot switch is working – see if the contacts continue to be working and that the wires aren't broken.

Check to see if the lubricant is adequate for different elements of the chuck, and that there isn't dirt or debris affecting the movements.
Check if the chuck is working on the basis of the MDI M-code command.

Check to see if the output of the solenoid is working. If it does, a damaged wire at the connector is actually a problem.
Check if the draw tube which connects the hydraulic cylinder and the chuck is working, and if it is loose.
Attention: An improperly clamped machine part can cause accident, damage or worse – injury to operator! Thus, it is important that parts are properly clamped by the machine tool.

#6 Power Supply Problems
Sometimes, the CNC machine tool's display or different parts might not work because of issues with the energy supply. To rectify this, make sure that the correct power and voltage is useful for the input side of the energy and supply. You should subsequently see if the output or secondary side is properly working.

Recommendation: Let a specialist do the check.

If you have no power or voltage reading is low, consider disconnecting the output wires with the energy off, and then switch on and recheck the output side. You can also check to see if the LED on the machines will work, and have a consider the fuses to see if they've blown.

A stable power supply is necessary and is the cornerstone for hassle free operations with any CNC machine tool.

Attention: Call a specialist for such checks on electrical parts or connections.

#7 Automatic Tool Changer Problems
Occasionally, you could face challenges with the automatic tool changer in your CNC Machine Tool. This could be resolved by learning every step of the tool changing process, and troubleshooting it by diagnosing what went wrong.

Check that the base, the gripper arm, tool holder, support arm and tool magazines will work properly and smoothly. Or examine the swivelling and mechanical arm action to see they work properly. Do also keep consitently the automatic tool changer and tool holders clean of chips and coolant.

#8 Machine Vibration/ Chatter
When your CNC machine vibrates when it's doing its job, it may significantly reduce the life span of one's tool, affect the durability of one's CNC machine, or undermine the quality of your machined part. You can detect this merely by listening to the noise generated – this could sometimes be very loud!

To eliminate this, you'll need to diagnose if its workpiece chatter or tool chatter. You can also adjust the RPM of one's machining process, so the frequencies of the machining process won't resonate with the material frequency.

Note: For machining centres it is vital to use balanced tool holders when working with spindle speeds above 8,000rpm. Otherwise, vibration marks are the first ever to be viewed on your own machined part. This will be followed by way of a shortened tool life and lastly, failure of the bearings of one's spindle.

#9 Overheating of Machine Tool
For high volume and long durations of machining, overheating may sometimes occur. Your CNC machine tool may hit temperatures of 150 degrees or even more within. This will negatively affect the result of your machining job, the tool used, in addition to the CNC machine itself.

To prevent this, make sure that you regularly clear all channels and clean the machine to be free from dirt, soil and material. Have a typical calendar of cleaning all metal shavings in addition to the liquids found in cutting.

Overheating of a device spindle comes mainly from extensive usage at highest rpm. A spindle with Greased Lubrication cannot be used over extensive hours at full rpm. A spindle with Air-Oil Lubrication is better, while an Oil-Jet Lubrication spindle, like what Hwacheon is using, does not have any problem to operate the longest hours even at maximum rpm.

Variations in environment temperature in the workshop also influence machine overheating. Wind / air drafts through doors or open windows may affect the accuracy of one's precision machine tool.

A good wide window where sunlight can shine in freely plus a cold blowing aircon can provide a happy feeling to your operators, but your machine won't relish it at all since it gets distorted in every its axis.

#10 Wrong CNC Machine Tool Partner
Finally, and perhaps above all, you'll need to find the right CNC machine tool partner to lessen the occurrence of machine problems and human errors.

Machine tool errors and mistakes may be costly within the long-run for your company. To ensure these are minimised, work with established and experienced CNC Machine tool companies offering an extensive after-sales maintenance, training and servicing package.

Designed and precision manufactured to rigorous standards of quality, Hwacheon CNC Machine Tools have one of the greatest durability and lifespan in the industry.