While using CNC (computer numerical control) machines allows shops to produce parts that are within very tight tolerances and virtually identical to each other on small or large volume production runs, there are still issues that can occur.
A professional service specializing in CNC grinding will have qualified staff on hand to prevent these common issues, which is one of the reasons hiring these shops over general metal working companies is important. When quality of parts and components matter, choosing the specialized shop over the general shop is always the best choice.
There are some common issues that customers may find with parts made by a CNC grinding machine. These issues often occur when the equipment operators have a lack of training with the equipment or when the equipment is poorly maintained.
Finish Problems
With a professional grinding service, the finish of the parts will be smooth, even and free from discolorations, blemishes, irregular surface textures or other variations. However, if the equipment is not set correctly or if parts or other components are not maintained or operated according to requirements, there can be noticeable exceptions.
* Striped look – this is sometimes called a barber pole finish and it is typically a result of incorrect lubrication or incorrect fitting of the centers to the spindles.
* Rough or burlap finish – often caused by vibrations in the tool or a tool that is loose. It can also occur if there is a problem with the hydraulic system that is creating an uneven movement of the tool.
* Burns or cracks – there many different issues that can cause burns or cracks on the surface. It can occur if the wheel is not correctly selected for the workpiece or if the grinding wheel or the spindle is moving too fast or too slow. Not enough coolant or the nozzle not correctly positioned to provide coolant where necessary can also be a cause of these types of surface issues.
Specific irregular grooves in the surface known as chatter marks can be an issue when the CNC grinding wheel is out of balance or is too hard for the surface. It can also occur when the program is not correctly designed and is attempting to grind too deeply.
Besides surface issues, problems with grinding equipment can result in asymmetrical or out of round holes, burrs on the edges of areas on the workpiece and poor control over tolerances. With a top grinding service, these issues will not be a problem, ensuring your order arrives completed to your specifications and requirements.
