Hardware in size, parts meet blueprint specifications, but surface finish and overall appearance are not ideal? When this happens, we need to go back to basics and make sure we use the best machining method we know.

We need to look at things like workpiece fixtures to make sure it's solid and it doesn't promote harmonic problems or vibrations during hardware processing. We need to make sure we don't use unnecessary long tools that can easily turn around or increase the chances of chatter. In high speed hardware processing, we need to ensure that a quality balanced tool is used, which has been rated according to the programming RPM used. But if all the things mentioned above are good, what should we do?

The following options are considered for hardware processing:

1. Control chip: chip evacuation is the key factor to produce good surface finish. The control chip may be the first thing you should consider. If the production chips come into contact with the workpiece during machining, or if you are re cutting chips, it is likely to affect your surface finish in a negative way. Consider the possibility of changing the style of the chip breaker you are using to help break down the chip for better control.

Although the use of air and coolant is a good choice to control chip removal, pay attention to the coolant. Avoid using coolant when cutting intermittently. Hot cracks in cutting edges can occur... Due to intermittent heating and rapid cooling of cutting edges... And can lead to premature blade failure, or at least start to affect your surface finish due to excessive stress on cutting edges and failure.

2. Increase speed: This is especially true when using cemented carbide tools. Increasing speed will ensure shorter contact time between the material and the tool tip... Thus reducing edge accumulation on the tool, which may result in poor surface finish. Increasing the rake angle of the cutting tool also helps to reduce and control edge accumulation.

3. Use the correct nose radius: larger nose radius will be able to adapt to faster speed. The insert can be fed at about half of the TNR per revolution and still produces good results. This "glossy" tool with "IPR" will create more glossy surfaces than you would if the surface were glossy. Therefore, the larger the TNR, the faster the feed rate it can accommodate and still produce the desired results. However, using very large TNR can produce chatter - reducing cutting pressure - so be careful and consider the speed required to cut the material - use a TNR tool that meets your needs.

It is also worth mentioning that using a larger nose radius means that you have to leave more material for completion through. To ensure that the tool works properly, you must have TNR equal to or greater than TNR in order to complete tool removal.

If you have chatter around the corner, you may want to try a smaller TNR. Always use TNR smaller than the corner radius you are cutting - so you can "form" the radius you need - especially on finishing tools. This will help to reduce cutting pressure and eliminate chatter.

When milling, try to use the fillet or spherical end mill instead of the plane end mill. Something with a fillet radius will give you a higher finish at the sharp corners and certainly help extend tool life.

4. Try to insert the wiper: as far as possible. The wiper insert has a small flat area adjacent to the nose radius. As the tool is fed along the workpiece, this plane actually "wipes" the finish and helps to eliminate the linear finish that can be encountered with faster feed rates - this allows smaller TNR to be used to help control chatter.

5. Increase the lead angle of the tool. Higher lead angle and positive inclined blade produce better surface finish than tools with shallow cutting angle. For example, a face mill with a 45 ° cutting angle will produce a better surface finish than a face mill with a 90 ° cutting angle.

6. Eliminate dwell and pause: every time the tool stops moving when it comes into contact with the surface of the part, traces will be left. Change the process if necessary, but try to make sure that the tool never stops or hesitates during the cutting process.