Automated machine tools have revolutionised industry but like any other machinery they can go wrong. A CNC failure is usually referred to as a crash. In most cases this only leads to the throwing away of the piece being machined, but in the case of a severe crash it can break the tool being used or even cause damage to the machine itself.
Causes of Crashes
Crashes can occur for a number of reasons. Many CNC systems have no sense of position so the table needs to be zeroed manually before starting work. If this is skipped or not done correctly then a crash will occur due to the machine being out of position.
Other problems occur on machines which blindly follow a sequence and continue to do so when things start to go wrong. This relies on the operator spotting when a crash is occurring and being able to stop the machine before things go too far. More sophisticated systems include load sensing which allows them to stop automatically if they detect an overload occurring. But even these machines rely on close operator supervision as some crashes may not cause an overload to occur.
Not all issues result in a crash. In some cases they’ll simply lead to a sub-standard component being produced. This can happen for a number of reasons; a blunt or damaged tool for example or an incorrect feed or spindle speed.
Problems can also occur if the machine isn’t maintained properly. Even not cleaning up can cause difficulties as dust and material shavings can get in the way of the tool and can push it out of position. Machines mostly use air to open and close tool holders so it’s important to ensure that airflow to the system is maintained at the correct pressure.
The same goes for lubrication; a good oil flow will ensure that the machine works effectively. It’s vital to make sure that all the moving parts are properly lubricated before starting work. If the machine has a cooling system then this needs to be regularly checked and kept topped up too.
Of course, as with any computer system, errors can arise from the software. It’s therefore especially important to take care when running a new program for the first time. Some systems will allow you to run them at a slower rate so that the operator can watch for problems. This allows bugs to be ironed out in the early stages before things get a chance to go badly wrong. It is possible to get simulation software that can be used to test out a series of instructions or even to train an operator in a new process without using the actual machine.
One of the advantages of having a computer controlled machine is that it can usually help you to determine what’s wrong. Most CNC machines will have a series of error codes that get displayed when something goes wrong. By ensuring that the operator is aware of the most common codes and the procedures to deal with them you help to ensure productivity. It’s useful to have some basic documentation handy near to the machine so that any more unusual errors can be looked up.
If you have a problem that can’t easily be identified and put right then go may need to call on a repair specialist. Specialist companies offer a repair and maintenance service for printed circuit boards in industrial machinery. CNC machines represent a major investment so you need to ensure that you look after them in order to get the maximum return.