An Overview of Post Processor CNC Turning Machining 2021

September 16, 2021

In articles about CNC, you will learn the basic general knowledge without going into each individual component of the CNC turning machining. And this will limit the ability to use the machine effectively and understand the parameters as well as intervene more deeply.

CNC Turning Machining

Because the articles go into quite detail and of course some terms may not be the same as the names at some companies, and if you find some words difficult to understand, you may not have a good picture, or have not common them. good machine.

Main shaft and tool holder in CNC turning machining

In a CNC machine, the spindle is the axis of rotation of the machine, often the key term to define the machine’s capabilities. Some CNC machines that specialize in mass production have a group of 4, 6 and more tool heads. These are called multi-head machines

CNC turning machining is nothing more than a spindle it is a motor that allows the tool to be inserted and removed; then the table moves, the system controls the motion of the axes, and the software calculates the rest.

CNC turning machining, spindle specifications

The spindle specifications in a CNC machining center are:

  1. First, maximum spindle speed
  2. Second, spindle motor power
  3. Third, spindle motor maximum torque

ATC (Automatic Tool Change):
In the tool tray, the tool change takes place using a clamping system also known as a lever. The change taking place with a two-handed clamping device after a new tool has been called in the NC program is as follows:
1-First position the desired tool in the magazine into the tool change position.

2-Bring the CNC turning machining, spindle into the changing position

3-Second, rotate the old tool holder in the spindle to the previous position and to the new tool position in the magazine

4-Moreover, return the tool clamp to its original position

An overview of post processor; CNC turning machining

Surely working in the field of machining you have heard a lot about Post Processor, but is it difficult or easy and what is its role? Don’t worry, it’s really not difficult at all, it’s just equivalent to the Find and Replace function like you type word.

But here, because of manual editing, as you usually do, it will have software, when copying the code over, it will automatically edit (replace, add, or subtract) the text (code) to suit. In CNC turning machining machine’s interpreter is merged.

Significance of spindle in CNC turning machining

The spindle is one of the important parts in a CNC machine and has a high value. Therefore, when an error or damage occurs, people often choose to repair the CNC machine spindle instead of investing in buying a new part.

1. CNC machine spindle structure

CNC machine spindles are divided into many types with different uses and advantages and disadvantages. Consists of:

  • First, belt-driven spindle
  • Second, main shaft driven by gears
  • Moreover, main shaft in CNC turning machiningis directly driven
  • Integral driven main shaft aka electric shaft

Composition of main shafts in CNC turning machining

But in general, the main shaft usually consists of 2 parts: the rotating shaft and the driving motor. These two parts are usually made of high hardness steel, have a slide to guide the tool head to move up and down in the Z direction and have ledges to hold the cutter.


Depending on the type of spindle, they have different structures such as. Below are the parts of the direct drive main shaft: Spring gear, bearing, cooling spring, rotary motor, rotating unit, stationary unit, clamping system, cooler, bushing, cutting tool surface are some aspects of CNC turning machining

CNC turning machine, spindle structure

Spindle is one of the most important parts of CNC machines such as CNC milling machines, CNC lathes. The spindle contains the cutters and rotates with them. Therefore, the accuracy, rigidity and motion stability of the spindle have an influence on the quality of products processed on the machine.

However, for mechanical equipment, the occurrence of errors and damage is unavoidable. Because the main shaft has structure and complexity as well as high cost, it is often repaired instead of buying new. To find out the errors and repair in CNC turning machining effectively, you need to understand the structure and types of CNC machine spindles.

Cause and repair of CNC turning machining spindle, shaft

– Cause:

The shaft is damaged because of wear after a long time of use.

– How to repair

  • First, if the wear is < 0.02mm, it can be grinded on a CNC lathe with a wooden clamp with abrasive paste.
  • Second, if the wear exceeds 0.02mm, grind with the repair size.

Precautionary measures for CNC turning machining

After grinding, CNC turning machining must check the hardness to see if there is still a layer of coal permeability or hardening? If the grinding loses the hard layer, it must be heat treated or chemically heat treated. When the shaft machining reaches the repair size, the bearing bushing must be replaced.

  • Firstly, if the shaft is worn down to 0.1 mm, it can be metal sprayed chrome plated or arc welded.
  • Secondly, cover the excess of machining because after turning, grinding must achieve the part.
  • If the shaft is worn a lot, it can be turned down
  • And then pressed for repair as a measure to restore the center shaft and transmission shaft.
  • Above all, fix the shaft failure by polishing

Installation of CNC turning machining

Install the shaft on the center points, the rotation speed of the shaft is about 50-70m / min. The polishing stone in CNC turning machining is a small piece of perlite cast iron. When operating, the handle of the cast iron piece lightly presses the surface with the grinding powder.

This is so, so the shaft and moves it back and forth along the shaft length for about 3-5 minutes. In the process of polishing the shaft, occasionally wash the abrasive powder attached to the shaft and the cast iron with gasoline, apply a new layer of abrasive powder to the cast iron and continue working.
CNC Turning Machining 2021

Repair taper hole in CNC turning machining

– Cause:

The taper hole is often damaged because of wear. Check for wear by contacting paint marks between the hole and the taper caliper.

– How to repair CNC machine spindle?

  • If the hole has little wear, it should be taken to a circular grinder in it to be repaired.

Then place the front end of the main shaft with the tapered hole to be ground on the dedicated support. Back end in grinder chuck. The permissible mounting error is 0.005 mm.

When grinding, CNC turning machining pay attention to ensure the original taper. If the taper to be sharpened is of the main shaft, the lathe can be left on the machine in the assembled form. Then use the clamp sharpener on the handover to grind the taper hole.

How to Recover losses by pressing silver?

If the spindle cone hole is worn a lot, it can be restored by pressing the repair silver like this. First, a low carbon steel tapered roller bearing 4-5mm thick is available, sized to be pressed into the spindle taper hole. To ensure concentricity between the center line of the taper hole after repair and the centerline of the main shaft.

It is necessary to leave the main shaft CNC turning machining installed on the machine (if it is to repair the taper on the main shaft of the lathe) but turn the taper hole according to the outer diameter of the bearing so that the length of the bearing when installed is snug in the turned taper hole of the main shaft.

Suction shaft type role in CNC turning machine

Penetrating silver hole 0.5-8mm deep, I arrived at HRC58-60. Then remove rust and dirt from the bearing, grease the silver outer surface and place it in the spindle taper hole. Use a suction shaft type patcher to firmly press the silver into the spindle taper hole. After pressing, grind the silver hole to the required smoothness and precision.