CNC machining is a metal fabrication method where written code controls the machinery in the manufacturing process. The code determines everything from the movement of the cutting head and the part to spindle speed, RPMs, etc. CNC machines are rather expensive so most shop owners buy used CNC machines. You can save a large amount of money versus buying a new machine, and often you will find that the seller is willing to throw in tooling and accessories for free. But some problems are included when buying used CNC machines. Used CNC machines have lower price tags than new ones, which makes buyers question the condition the machine will come in. Many buyers know that a used machine can have hidden issues that will end up costing more to fix, than the initial price of buying a new one. Here are some things to look for to avoid issues with used CNC machines:
Improper Care – Common mechanical issues often arise from improper care. Ask your sales representative if there is any documentation of the machine’s past maintenance. Reading over the documentation will let you know if the machine has had any recurring problems. Poor or Improper Maintenance CNC machines need to be carefully cleaned and lubricated regularly otherwise, problems can begin to arise. A lack of cleaning could lead to a buildup of dirt and debris.
Inadequate Electronics – Several of the maintenance issues with used CNC machines is related to their electronic and wiring components. Even if a machine runs well and looks fine from the outside, it may have wiring issues. Ask your inspector if the original wiring has been replaced or repaired. Electronics are also as prone to malfunctions and breakdowns like any other machinery. And when your electronics stop working, it can be difficult to know what to do about them. The same factors that make them so precise and efficient on the job also make them intricate and complex devices to repair. As mentioned above, ask your sales representative for any past repair documentation and make sure that a certified CNC machine inspector approves of the machine’s interior before committing to buying. On the other hand, when you do not pay attention to the electronic and wiring components of the CNC machines, you will miss out on something. It could be difficult for you to handle the CNC machines that have damaged electronic and wiring components.
Unserviceable Equipment – Even if a particular machine runs well, it is important to ask the seller if it is still serviceable by the OEM (Original Equipment Manufacturer). If the machine were to malfunction, it will be either impossible or very expensive to repair due to the unavailability of a qualified repair person or spare parts. Furthermore, you should determine the serviceable equipment of the CNC machines. The components and equipment should be highly serviceable if they have some problems. In most cases, it is better to spend more on a serviceable machine that deals with any issues it has later on.
Outdated Controls – This could become yet another big mistake while buying the used CNC machines. In the same vein as serviceable equipment, outdated controls can be an issue with many used machines. Much like old computers, older controls are obsolete and cannot run modern software, and as such, cannot operate newer tooling. Most of the buyers know that a used machine can have some hidden problems that can end up costing more to repair than the initial price of a new CNC machine. While it is possible to update or retrofit the controls on a machine, the cost of replacing parts usually defeats the economic incentive to buy a used machine. You can hire a certified and qualified technician who can inspect the CNC machine before you make the final call on buying it.
Poor or Improper Programming – Another issue that could lead to serious problems in your CNC machining is incorrect programming. This is a simple cause-and-effect problem since the programming directly controls the creation of the product. Therefore, if the programming is incorrect, the product will have problems. As highly sophisticated equipment controlled by CNC computers, much of the issues which arise in CNC machining often come from programming. These may come from a lack of understanding of the different G and M codes used for the controller, wrong set-up, or inputting the wrong data variables into the CNC controller. To avoid this scenario, make sure every employee receives full and proper training on how to correctly code a CNC machine. This way, these kinds of easy-to-avoid mistakes will be less likely to happen, and you’ll be more likely to have a smooth and issue-free CNC machining process.