4 Aspects of Controlling CNC Machine Shop Quality

The term CNC stands for “Computer Numerical Control” which is commonly used in manufacturing and industrial applications. CNC machine shops are operated by manufacturers who prepare the specific branded products or by any third-party manufacturer who owns the product or offers custom online machine services across the different industries. Want to fully know more this aspect, you may visit the blog.

Why Quality Plays an Important Role in Product Development?

When you go into a CNC machine shop, what you see most are the CNC machine equipment such as milling, turning, grinding, EDM, etc. But you also see some inspection equipment and many process documents are printed and pasted on the wall to instruct the manufacturing procedure in strict accordance with ISO 9001 standard. They both have an aim to control the quality, because the high quality means less time consuming and cost-effective for product development, which is important for the customer to occupy the market quickly.

How to Control the Quality in a CNC Machine Shop?

From the moment of receive the customer’s quote request, the quality control is starting. Fully understanding about the customer’s project and quality request can provide an accurate quotation. The quality control can be throughout the entire process until the product is shipped. A CNC machine shop can control the quality from the below aspects:

Fully Understanding Customer’s Quality Requirement

Before the order, the company will interact with the customer to understand their product requirements. The company will ask for what purpose the customer wants to use the product. Then, the company will help its customers to reduce their design manufacturing cost by knowing the details of customer usage. Selecting the appropriate tolerance, molding material will help you to obtain a high-quality product, ease in manufacturing, less time consumption, and easy to market the product.

If the customer does not know how to choose the right tolerance or any other feature of the product for your proper functioning, feel free to contact us. The company will guide you properly on the important facts of the decision before selecting the tolerance at a reasonable price. It will help you to make a proper decision about your tolerance demand for your project.

In-coming quality control

There are so many materials that can be used for CNC machining, including varieties of metals and plastics, such as aluminium, acrylic, PC, etc. These raw materials all have many grades and different quality accordingly, a good CNC machine shop will strictly check the incoming quality, which is the first quality checkpoint before production. The purpose is to move quality control forward, reduce quality cost, and achieve effective control. If unqualified products are put into the process, it will lead to unqualified products in the process or final products, causing huge losses.

In-process quality control – the inspection of the first piece

The first inspection in the production process is mainly to prevent the occurrence of batches of products out of tolerance, repair and scrap. It is a means of pre-control of the production process of products, an important method of production process quality control, and an effective and essential method for enterprises to ensure product quality and improve economic benefits.

The final Inspection for Quality Control

As the products have been prepared by the CNC machine, they will go to the inspection and measurement process to check whether the obtained design is up to the mark or not. These processes are performed by some tool which briefly explained below;

  • Coordinate Measuring Machine (CMM):

It is a device with an electrical probe that measures the dimensions of any mechanical part by sensing discrete points on the surface of the object. It works based on three axes x, y, and z. It takes a reference position of the Cartesian plane and moves the probe around the object to create a point cloud of the shape of the part designed by the machine.

  • 3D Scanner:

It is an efficient and cost-efficient method of scanning the products directly into the CNC machine.  It measures the dimensions of the products for their quality control. It is capable of capturing thousands of points plotting in a matter of seconds. Complete scanning can be done in a fraction of time depending upon the size and complication of the part. 3D scanner accurately measures the part against the original design.

  • Digimatic Holtest:

It is an internal micrometer which is coated with tin and provides a contact point to allow the instrument to measure of the blind hole. An extensive rod is sometimes used to measure the deep holes.

  • Full range Digital Vernier Caliper:

Vernier Caliper is broad in size, shape, and sophistication range. It measures by the simple principle by placing the two tips at the distance to be measured. One tip on the starting and another tip on the ending point of distance. It shows the reading on the digital dial attached with it which is easy to read due to digital screen.

  • Gage Block:

Gage blocks are the system of measuring precise length. These made up of metal or ceramic material with some lapped thickness. Gage blocks are in the form of the set having a different length to be measure. They can be joined with each other having little uncertainty.

  • Surface roughness and hardness tester:

Surface roughness quickly measures the surface texture with the roughness depth and mean roughness in micrometers. Then the area of depth of indentation inferred the hardness of the material.

  • Digimatic Heitht gages:

It is a classified method of inspection with versatile multi-functioning. It provides coarse and fine feed switching. It has electrostatic capacitance linear encoder which gives repeatable and precise measurements.

  • In process Tool Probe:

A probe tip is perpendicularly mounted on the three rods; each rod is surrounded by two metal balls. When the probe touches the edge of the milling part, the circuit breaks and it delivers the signal to the CNC control box. In this way, the material is inspected during the process.


Choosing a CNC machine shop that provides the best quality control for customers during their product development phase, because the high quality means less time consuming and cost-effective. A good CNC machine shop always focuses on the quality control, not only on customer communication to check the detail quality requirement, but also on the IQC, PQC, and final inspection before shipment.