PROCEDURES OF CNC TURNING

To help you understand what is CNC lathe. HESEM introduces the definition of the CNC lathe and related knowledge about CNC turning. Hope you have more information to serve your CNC turning orders become better

What is a CNC lathe?

A CNC lathe or computer numerical control lathe is a machine that rotates material around a central spindle and a stationary cutting tool. The movement of your material is dictated by a CNC program via a computer rather than being operated by manual labor.
This CNC turning machining process is suitable for machining a wide range of materials, such as metal, plastic, glass, and wood, and for the production of a variety of tailored parts and products.

This article focuses on CNC turning, outlining the steps of the CNC turning process.

CNC turning process

Like most conventional CNC machining processes, the CNC turning process uses computer controls to operate and manipulate machine tools that cut and shape the parent material. In addition, the process follows the same basic manufacturing stages that all CNC machining processes follow, including:

1. Design CAD model for CNC turning

The CNC turning process begins with creating a 2D or 3D CAD part design. Currently, most outsourcing companies use 3D models for CNC turning. This process is usually performed by mechanical engineers. Popular CAD software today: Fusion 360, Inventor, Solidworks, Top solid …

2. CNC programming for CNC turning

The CNC programmer will use the 3D model to conduct CNC programming. Based on the shape, size and technical requirements of the part to be processed.
The programmer will provide the machining technology process, design jigs, and make a list of the necessary equipment to prepare for the machining process. They will then use the functional commands of the CAM software to generate toolpaths for the CNC lathe.
After having the toolpath and the appropriate cutting parameters (cutting speed and spindle speed), they will proceed to compile the toolpath through a post-processor.
This compiler software is designed specifically for each machine. It will translate these toolpaths into G code lines. The CNC lathe understands these G-codes and executes the same toolpaths as those programmed in the CAM software.
To ensure that the compilation is error-free and that errors are detected during toolpath generation. This G code program will be used to simulate cutting on cutting simulation software such as NC Simul, Vericut, CIMCO Edit, or online solution NC VIEWER
Popular CAM software today: Fusion 360, MASTERCAM, CIMATRON … In which, Fusion 360 is the most outstanding solution today with the best cost-on-function approach. Very suitable for small companies that can use copyrighted software with the lowest cost and the most flexibility.

3. Preparatory operations on CNC lathe

Before CNC milling is started, the Machine Operator must perform the following steps:

Mounting fixture and workpieces on CNC lathe spindle

Different from the CNC milling machine, the workpiece and jigs are fixed on the machine table. Machining CNC turning workpieces and jigs on the main shaft.
The requirement of this step is to ensure that the workpiece and fixture are positioned and oriented correctly according to the programmer’s instructions. At the same time, this step must ensure that the workpiece is firmly fixed on the spindle and does not move during machining.

Mount the CNC turning tool on the tool holder

Based on the tool table that the programmer sent with the CNC machining program. The operator proceeds to attach the turning tool to the tool holder.
This step requires the operator to select the correct tool holder and the required tool type. At the same time, it must be tightened carefully so as not to splash the knife during the machining process.
After preparing the tool, the operator proceeds to attach the lathe tool to the lathe insert. This step requires the operator to properly mount the tool in the magazine indicated on the tool plate.

Input tool offset to the machine memories

The setting of the machining standard is carried out as follows:
Bring the tool tray to the machine reference point R (Reference) by the control button of the machine.
Select the manual travel mode, and at the same time let the spindle carrying the workpiece rotates.
If the workpiece origin X0, Z0 is selected at the top face of the workpiece. Proceed to determine the 0 points of X and Z as follows:
Determine the 0 points along the Z axis
Use handle mode for the feed to touch the head. When touching the head face, record the result of the Z axis (eg Z = – 770.34 ) and enter it directly into the machine.
Go to OFFSET/ OFFSETTING/ SELECT GEOMETRY mode enter Z0 and press MEASURE.
Thus, the zero point of Z has been determined. If you enter the result of Z directly, press INPUT.
Determine the zero point along the X . axis
Use the handle mode for the tool to touch the back of the part. Move the Z-axis tool out of the workpiece. Record the results on the display (e.g. X-170.34). Then measure the workpiece size (eg D = 40 mm).
Enter OFFSET/ OFFSETTING/ SELECT GEOMETRY mode enter X40. Press MEASURE.
Or enter X = ( X displays – D workpiece )/2 press INPUT.
Thus, we have set the zero point of the workpiece.

Double-check all the above steps

Double-check all parameters one last time, and make sure no errors are missed. This step is very important because if there are errors, there is a possibility of crashing the machine causing great damage to the factory.

4. Perform CNC turning

The CNC lathe in the CNC turning process will read the command code and return all G codes to the default value.
The CNC lathe will continue to record cutting parameters such as spindle rotation speed, and cutting speed for functional commands such as turning on coolant and closing the door. These values will change based on the CNC turning program during running.
The CNC lathe will sequentially read each command from top to bottom to determine the position to move to. Each command line will contain the position to move or the function commands and also include the position to move to and the function commands.
After receiving the position to move, the CNC machine will send pulses to the servo motor to move. The CNC milling machine will finish moving the tool head to the position called in the program and then proceed to the next position.
This process sequentially executes to create the machining motion that the programmer has previously created on the CAM software. 

5. Inspection of the CNC turning part

After the CNC turning part is completed, it is transferred to the quality control room to measure and evaluate the machine part against the customer’s technical requirements.
If the part meets all the criteria, it will be packaged and delivered to the customer. If it has an issue, it will be reworked or machine.
To ensure production progress and costs, an additional process inspection will detect errors as soon as the part is on the machine.
QC guy uses measuring devices such as calipers, micrometers, altimeters, photometers, CMMs, and roughness meters.. to check product dimensions.

Epilogue

The above presentations, hopefully, will help customers understand more about the processing steps so that they can coordinate well with the finishing processing units to get the desired product.
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Factory contact information

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– Phone: (+84)985994010
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