6 tips for maintaining tight tolerances in CNC precision part machining

       In CNC precision parts processing, six techniques to maintain strict service requirements, CNC machining mechanics like to see such equipment: +/- 0.005". Five thousandths of an inch is for any good mechanic training - they may wish Close your eyes and grind them. However, those jobs require a higher amount. Add another zero, now you have: 0.0005". Holding five tenths of you is a completely different story. This is the difference between the thickness of human hair and white blood cells. When it comes to strict servitude, here are some suggestions to maintain your part specifications.

       1. The main shaft warms up to maintain tight tolerances
Running a warm-up program - Although this is a standard procedure for a large number of CNC machines, the study runs some more complicated things. A typical procedure only preheats the spindle, which is critical for applying smooth grease to prevent premature bearing wear. However, you also need to allow internal components to reach a stable operating temperature to cope with thermal expansion. Now, if you only want to maintain a strict servitude on the Z-axis, all of this is accurate, but if you combine the spindle warm-up with the machine's movement on all axes, this will help further. The machine is allowed to run for 10-20 minutes, all parts move the promised parts to the dream temperature, and will help reduce the effects of thermal expansion during milling time. No matter what, at the end of the warm-up, ensure that all equipment is accurately measured and that strict servitude is maintained.
Tool selection may be a factor in maintaining strict servitude. Roughing equipment is used for “roughing” to reduce the wear of the finishing tool and maintain accuracy.
       2. Maintain equipment selection for tight service
Choose your equipment carefully - when you deal with these intolerant servants, it must be suitable for your equipment. You need to ensure that you have specific equipment for roughing and finishing, so that roughing tools can receive wear, while finishing tools only save the next step, ensuring a repeatable process of creating accurate parts.
      3. Strictly tolerated compensation
Reimbursing your equipment - The equipment manufacturers are not happy, so the equipment they designed is a bit tolerant. They know that if you want to use their equipment to do something, if the performance of its reduced performance is too large and not too large, you will be more happy. Just like shaving the same head: you may wish to take a rest, but you can't put it back. Know this, you need to make sure that the first thing you do when configuring an accurate job is to dial the diameter of your essential equipment. You may wish to do this in a variety of ways, but my preferred method is to mill a feature and then use the exact equipment to verify the size. Very simple - if you use a 0.236-inch tool to insert a 0.250-inch hole, only a 0.248-inch gauge pin can be inserted, so your tool size will be reduced by 0.001 inches (because the size of each side can not be small, so use half value).
       4. Maintain the temperature of the tight service
Hot and stable - This is one of the important things in the list, because it can make a huge difference, and you may not even pay attention to it. Please pay attention to the location of your mechanical location. Is it close to the window, if it is, then at some point in the day, is the sun on it? Does the air conditioning system start in the afternoon and blow the cool air in the cabin? Is your raw material stored in a stuffy warehouse? Then enter the cold 68 ° environment? These seem to be innocent, but will create huge difficulties in your process. Thermal expansion or contraction of the milling machine or cutting material can make a big difference in your machining process. Put all of this in lock - maintain your machinery and raw materials in a temperature-controlled climate, unaffected by the sun, and you'll be rewarded with a reward - a generality in your process.
        5. Maintain tight calibration
Calibrate your device - When you're done with all of the above, but what you need is just *that* is more rigorous, research calls at the manufacturer. After a machine is built, it is transported, dropped from the truck, moved, stabilized, and used for thousands of hours, things will be transferred and processed. This is unpreventable. Fortunately, there are several pieces of equipment, whether it is a granite box or a Renishaw Ballbar, it may be helpful to help loosen the elastic mechanical reins to help maintain the battle. We like to do a club test and adjust it as part of the annual care, so you can maintain a close relationship with the precision of the machine. In addition, the implementation of these annual services ensures that the bearings are tight and smooth, the belts are properly tensioned, and the drive motors operate well - these are important factors in the accurate machining of machinery.
       6. Linear scale for maintaining tight service
If all failed, the scale! - If you are still doing all the work on this list, and still working hard, then it may be time to study the linear ruler to get the machine. Your typical CNC machine will use a drive motor encoder as a key way to track its absolute position, but this may be due to the ball screw's shortcomings or temperature differences. The linear scale changes all of this - usually installed at the factory, they consist of two key parts - the ruler and the read head. In short - the scale is like a high-precision ruler that the machine can read, constantly checking and adjusting the error. On our M10Pro, it is possible to complete a 25% more stringent positioning campaign with a 20% increase in repetitiveness and a 85% reduction in backlash.

Hopefully these reminders can help you better guide high-precision machining and maintain the long, inflection, vibration (but still beneficial) path of strict service.