Ensuring Precision: Quality Control In CNC Machining

Last updated

Table of Contents

As a CNC machining manufacturer, producing high-quality parts that meet the required specifications is essential.

Quality control measures help eliminate errors and produce reliable products.

By implementing stringent quality control measures, manufacturers can improve their manufacturing processes, reduce the risk of defects and improve customer satisfaction.

This blog discusses the importance of quality control in CNC machining and how it can ensure manufacturing accuracy with many standards.

Importance Of Quality Control In CNC Machining

Quality management measures are essential in manufacturing processes like CNC machining because they help to ensure that the finished product meets the required quality standards. These measures are designed to detect defects and ensure the output is consistent and accurate.

By implementing quality control measures, manufacturers can detect potential flaws early in production, correcting defects before the final product reaches the consumer.

Quality control measures are essential to ensure product consistency, accuracy, and customer satisfaction.

CMM machine

Quality Control Processes

Material Inspection Before Machining

The material inspection involves inspecting raw materials for imperfections or defects that could affect the quality and reliability of the final product.

Here are some key areas to focus on during material inspection before machining:

Surface Inspection: During this stage, the material’s surface is carefully examined for surface anomalies such as cracks, chips, rust, or other surface irregularities. Surface defects can result in machining errors or weakened parts, leading to reduced performance.

Dimensional Inspection: Using a coordinate measuring machine (CMM), we carefully inspect the material to ensure it conforms to the required dimensional specifications. The inspection thoroughly checks the material’s thickness, width, and length.

Material Properties Inspection: By examining the material properties, we can ensure the materials are suitable for the intended application. The inspection includes hardness, tensile strength, elasticity, flexibility, compressive strength, and other properties depending on the intended function of the machined part.

Chemical Composition Inspection: Chemical composition plays a significant role in determining the parts’ performance, especially in industries where environmental exposure can affect the parts’ durability. Therefore, inspecting the material’s chemical composition is crucial to ensure it meets its requirements.

Quality Control In CNC Machining

Setup Verification

Setup verification in CNC machining involves verifying that the CNC machine is correctly configured to produce the desired final product.

The objective is to ensure that the machine settings are accurate, the tooling is correctly positioned, and the cutting parameters are correctly programmed to achieve the required specifications and tolerances for the final product.

The setup verification process typically involves several steps, which may include the following:

Verifying that the workpiece is properly aligned and fixtured to the machine. This involves checking that the workpiece is held securely and that the machine’s clamps or fixtures are configured correctly.

Verifying that the tooling is correctly installed and adjusted. This includes checking the tool length offset (TLO), the tool radius compensation (TRC), and the correct tool installed in the spindle.

Checking the machine offsets and adjusting them as needed. This includes setting the correct workpiece origin, tool offsets, and fixture offsets.

Running a test program to verify that the machine is running correctly. This involves running a small test program to check that the machine is moving correctly and that the programmed toolpath produces the desired results.

Performing a quality inspection of the test part to confirm that it meets the required specifications and tolerances.

In-Process Monitoring

In-process monitoring involves monitoring tools and sensors to detect issues during machining.

It aims to identify any variations, defects, or other issues that can affect the quality and accuracy of the final product. So they can be corrected in real-time, reducing the risk of waste and rework.

In-process monitoring typically involves several steps, which may include the following:

Measuring the cutting forces: One of the most common forms of in-process monitoring is measuring the cutting forces produced by the CNC machining process. This can help detect variations or defects in the cutting process caused by tool wear, material hardness, and feeds. The data is analyzed in real time by monitoring systems that adjust the machining parameters to maintain optimal process conditions.

Verifying the dimensions of the workpiece: Another aspect of in-process monitoring is verifying the dimensions of the workpiece as it is being machined. This can be done using non-contact sensors or probes to measure the part’s diameter, length, and other geometrical properties. This ensures that the part conforms to the required specifications and tolerances.

Monitoring the temperature: Monitoring the temperature of the workpiece, the tool, and the machining environment is critical in preventing overheating. It can affect the accuracy and consistency of the machining process. This can be done using thermal cameras or sensors deployed to measure the temperature changes in real-time and adjust the machining parameters.

Record Keeping: Keeping track of the data gathered through the CNC machining process allows the company to identify patterns or potential issues. It improves operational efficiency and produces high-quality parts.

Final Inspection

Final inspection in CNC machining ensures the parts produced meet the desired specifications and are high quality.

It involves a thorough review of the finished product by a trained inspector to ensure that it meets the design specifications, is free from defects, and is fit for its intended purpose.

The inspection involves measuring instruments to check the part’s dimensions, surface finish, and other crucial parameters.

In addition to the physical inspection of the part, the final inspection in CNC machining also involves reviewing the documentation associated with the part. This includes verifying that the correct materials were used, that the correct machining process was followed, and that any special requirements, such as tolerance or surface finish, were met.

How We Do Quality Control For CNC Machining Process And Products

Learn About The Industry Background

Based on the different standards in various industries, we need to understand the industry background when we receive an order, other than focusing on design drawings. For example, medical and military parts should generally come in outstanding precision, absolute safety, excellent quality, and tight tolerance, which may need to withstand extreme conditions.

Understand The Design Of The Product

When the customer sends the CAD drawing of the final product, the engineer needs to analyze the design files in detail, determine design intent, understand the customer’s product specifications and requirements, evaluate machining strategies, and check every detail before production. We will use the most cost-effective solution to process your parts, control the factors in the entire CNC machining process, and meet the requirements.

Train Personnel

Ensure that everyone involved in the quality control process understands the plan and their roles in it. Conduct training sessions to familiarize the team with the quality standards, quality control plan, and procedures.

Check Out Parts With A Precise Measuring Device

A precise measuring device, such as a micrometer, or caliper, helps to measure the physical characteristics of the machined parts. It provides an objective assessment of the machined parts. It enables machinists to identify any deviations from the design and make adjustments accordingly.

Do An Inspection When The Part Is Running

Inspecting the parts during continuous machining operations enables machinists to detect any issues promptly and make necessary corrections. This helps prevent errors, improves the quality of the finished product, and reduces the likelihood of project delays.

Communicate With Customers

Whether in the manufacturing process or after sending a sample, it’s effective to communicate with customers timely. Buyers and clients will have clear requirements on the product specification and function. When receiving an inquiry from customers, we will contact them quickly and give a free quotation as soon as possible. If something does not get right, we’ll adjust the solution instantly. For special requirements, please tell us in advance.

Our Quality Control Measures

Here are some of the key quality control measures used in our CNC machining:

Customer Communication: Effective customer communication is the basic element to achieving customer satisfaction. In manufacturing or after sending samples, timely communication with customers is effective. Buyers and customers have clear requirements regarding the specifications and functions of the product. When receiving an inquiry from a customer, we will contact them as soon as possible and give a free quotation. If there is something wrong, we will immediately Adjust the solution. If you have special requirements, please inform us in advance.

Understand The Design Of The Product: When the customer sends the CAD drawing of the final product, our engineer will analyze the design in detail, understand the customer’s product specifications and requirements, and check every detail before production.

Carefully implement the quality inspection process: By following the steps about quality control processes, our manufacturer can implement a robust quality inspection process and guarantee the quality of the CNC machined components.

To equip CNC mechanics with basic skills and knowledge: Our CNC mechanics have the basic skills of CNC machining and knowledge of quality control to ensure the production of high-quality parts.

Our CNC Machining Quality Control Instruments

Several quality control instruments can be used in CNC machining, including:

The vernier caliper-It can accurately measure the dimensions of parts or components, ensuring they conform to the required specifications.

Projector– Projector can be used to measure and inspect two-dimensional features of machined parts in a highly accurate and efficient manner. It works by projecting the magnified image of the part onto a screen or surface, allowing measurements and inspection to be conducted without touching the part directly.

Coordinate measuring machine (CMM) – This machine measures the geometry of a part to verify that it meets the specifications.

Digital height gauge – This instrument measures the height of a surface or feature on a part to ensure it is within tolerance.

Optical comparator – This instrument uses light to magnify and compare a part to a master part or design drawing.

Thread gauges – These gauges are used to check the accuracy of threaded holes or bolts.

Microhardness tester – This machine measures the hardness of a part, which can indicate its strength, durability, and suitability for its intended use.

Surface roughness tester – This tool measures the roughness of a surface to ensure it is smooth enough for its intended application.

Spectrometer – This instrument can analyze the composition of a part to ensure it meets the required specifications.

Choose Our Ejcnc Machining Services

As a CNC manufacturer, our CNC machining services are unmatched in precision, quality, and flexibility. Our CNC machining processes prioritize quality control and ensure our quality.

The company’s state-of-the-art CNC machines are equipped with the latest technology and operated by highly skilled machinists dedicated to delivering our clients’ best results.

Our CNC machining capabilities are tailored to meet the specific needs of each project, ensuring that every piece is produced with accuracy, consistency, and speed.

From prototyping to production runs, we can handle any job, regardless of size, complexity, or material.

Our commitment to innovation, attention to detail, and customer satisfaction make us the go-to choice for all your CNC machining needs.


CNC Machining Quality Control Standards

Thread and tolerance

In CNC machining, thread tolerances are of utmost importance to ensure the proper functional operation of the final product. While manufacturing externally or internally threaded components, manufacturers should closely consider the thread tolerances mandated by the ISO 965-1 standard.

The standard suggests metric thread tolerances should follow the 6H and 6g thread tolerance grades for internal and external threads, respectively.

Surface roughness

The surface roughness of the product is evaluated for any defects, such as scratches, pits, or unevenness. The product specification or drawing usually specifies the acceptable surface roughness level.

Color and Texture

The color and texture of the product’s surface are inspected for uniformity and consistency. The presence of discoloration, blemishes, or dullness may be unacceptable, depending on the product’s intended use or industry standards.

Cracks and Burrs

The presence of cracks, burrs, and other surface imperfections is evaluated. Any such defects could indicate compromised product integrity and may need to be removed or addressed by further processing.

Dimensional Tolerances

The dimensional tolerances are evaluated according to the drawing specifications to determine if the product meets the required size and shape. Any noticeable deviations beyond the acceptable tolerance range could render the product non-conforming.

Benefits Of Quality Control In CNC Machining

Lower Production Costs

CNC machining quality control measures can help reduce manufacturing costs in several ways:

Reducing rework costs: Quality control measures can help identify and rectify production errors early, reducing the need for reworking the machined parts. By addressing errors during machining, production time and materials are saved, ultimately reducing costs.

Enhancing machine efficiency: CNC machining quality control measures can help to improve machine efficiency by detecting any fault or defect that may affect the operation of the machine. This can aid in preventing machine downtime and costly repairs required in case of mechanical or operational breakdowns.

Eliminating waste: Utilizing quality control measures can help reduce the amount of waste produced during the CNC machining process. Raw materials and finished products can be conserved through efficient measurement practices and process optimization, reducing costs.

Increasing productivity: Improved implementation of quality control measures can lead to reduced downtime and improved machine efficiency, leading ultimately to increased productivity. Enhanced productivity reduces the time required for machining each part, and the total number of parts manufactured in a shift increases, thus reducing production costs.

Better Quality Finished Products

Here is how CNC machining quality control measures help to achieve higher-quality finished products:

Error detection and correction: CNC machining quality control measures help identify and rectify production errors before products are completed. These measures involve inspection, testing, and calibration that help identify errors, deviations in tolerances, or other defects the product might have. This allows for necessary corrections or adjustments, resulting in higher quality products and minimizing the risk of faulty products or rejects.

Maintaining tolerances: CNC machining quality control measures ensure that machined parts meet their required tolerances. When parts consistently meet tolerances, there is less rework, less wastage of material, and fewer defects in the finished products. Parts with consistent tolerances also fit well together, resulting in a higher-quality finished product.

Improving part accuracy: By using quality control measures, manufacturers can ensure that the end-machined parts are accurate and meet the required specifications.