What are the Most Problems and Solutions for Custom CNC Machining?


CNC machining is gaining popularity because of lots of CNC machining advantages and production machining commendable CNC parts provided by an online machine shop. We can customize the custom CNC machined parts to grow our business and for automotive or medical devices etc., through custom CNC machining services. Our online CNC machining services include CNC turning, milling, drilling, and other CNC machining operations, and you can receive manufacturability feedback for your design.

The machining CNC process is carried out through machines that function in an automated fashion to complete the development cycles of CNC machined products. The computerized controls program controls the functioning of these CNC machines through CAD files to produce custom machined parts after getting CNC machining quotes. The CNC machining work on instructions of the CNC machining quote and CAD file directs the CNC machines to carry out a specific custom CNC operation.

Moreover, the resulting custom CNC machining products show greater functioning and accuracy because of the rapid prototyping process before manufacturing the final CNC components. The manufacturing operations of custom CNC parts not only save time but also reduce costs because of low-volume production runs.

In this article, we will learn the problems and the solutions associated with custom CNC machining and custom CNC parts.

What is custom CNC machining?

Custom CNC machining or computer numerical control machining is a subtractive manufacturing method in which custom-designed CNC parts are created by cutting and removing material from a workpiece. The machining process involves specific machines or equipment changing the part geometry. The computer-operated programs carry out and control the functioning of this equipment and machines. The methodology of the CNC machining process is different from injection molding and 3D printing because of the computerized controlled tools. 

During the custom machining process, the custom parts are manufactured by chipping off the layers of the workpiece. As a result, the manufactured CNC machined component is utilized for various industrial applications.

In the present time, it is an extensively adopted manufacturing technique on the industrial scale. It doesn’t restrict any material during the machining task; we can use large quantities for machining CNC.

To manufacture custom parts through custom CNC machining, we can use bulk material, including:

  • Wood
  • Glass
  • Metals
  • Plastics
  • Sheet metal
  • Steel parts
  • Stainless steel

The CNC machined part becomes an excellent electrical insulator. The CNC machining process is cost-effective and offers higher accuracy and precision of CNC machined parts compared to the 3D  printing and injection molding methodologies. 

Problem 1- The Workpiece Size is Accurate but has a Poor Surface Finish

Suppose the surface finishing of the resulting production parts is poor instead of CNC machining a workpiece with accurate size and better surface treatments such as zinc plating, powder coating, or electroless nickel plating. In that case, there are possibilities for the following reasons. 

This helps companies manufacture thousands of similar and developed components quickly and at a potentially lower cost, providing streamlined services to create precision parts.

Resonance Generated by machine Tool during the machining operation.

Resonance is produced by the machine when it is not smoothly placed. It can cause poor surface finishing of custom CNC machined parts instead of properly placing the workpiece.  


In this case, fix the machine after adjusting it to the horizontal position to ensure lower corrosion resistance and better surface finishing of the machined parts. 

The machine’s tooltip is not sharp

The sharpening of the machine tooltip may reduce because it may get damaged or worn. It can cause machining defects and, ultimately, a bad exterior finish. Moreover, after post-processing treatments, the resulting component will have a defective texture finish. As machined parts are produced with poor surface finishing, they may face more corrosion and wear because of reduced corrosion and wear resistance capabilities.


We can solve this problem by directly resharpening the tool or choosing another machine tool with a sharp tooltip during CNC machining.

The machine tool has crawled:

Inadequate maintenance of the machine is the major reason behind the machine crawling and undesirable surface finishing of the CNC machined parts.


To solve this problem, enhance the number of machining tools during CNC machining for stable maintenance. Moreover, adding lubricant and cleaning wire are also recommended to reduce the friction produced during CNC machining. 

Problem 2- The surface roughness of the ordinary high-speed precision machining lathes cannot meet the requirements.

Cutting speed of lathe change during machining:

The CNC  lathe machine can commendably machine the components with uniform or small surface roughness values because of its constant linear cutting speed.

The surface roughness mainly depends on the lathe’s cutting speed and feed rate. Any changes in the cutting speed of the lathe can cause surface roughness even after an accurate CNC machining process.


To attain a consistent surface roughness, use your lathe machine’s constant line cutting fiction to select a suitable line speed for cutting spheres and cones.  

Problem 3- There is excessive resistance during the CNC metal machining and drilling.

Wrong Setting and Inappropriate Cutting Tool During CNC Metal Machining and Drilling:

We can use hard and soft metals for CNC machining and drilling. Using an inappropriate ratio of feed speed and a wrong cutting tool can cause excessive surface resistance during the CNC machining process.

It may cause burn marks, cutter marks, or raised marks on the corners and edges of the machined material. Moreover, the higher resistance may also cause the rough edges of the material resulting in a poor surface finish of CNC machined parts. 


The best solution to the above-discussed problem is choosing the appropriate feed speed ratio and the right tool during the CNC metal machining and drilling. It not only smoothly machined the metal part but also caused an excellent finish.

Poor Maintenance of CNC Machine Tools in CNC Rapid Prototyping:

One of the main reasons behind the high surface resistance during the CNC metal machining and drilling is the poor maintenance of CNC machine instruments.

When the CNC tools are not regularly cleaned and maintained, their performance is highly affected because of the accumulation of dust or debris particles. 

As a result, the tools cannot properly cut or remove the material from the workpiece, causing higher resistance. The high buildup of dirt can even lead to machine failure and machining inaccuracies.


To overcome this problem, we must clean and maintain the CNC machine instruments for uniform material removal and cutting. Moreover, we must also regularly check the airflow or coolant levels for a low friction level. It helps greatly in reducing the excessive resistance between the machine tools and metal parts. 

Inadequate handling of the CNC machined metal parts:

Proper adjustment and handling of the manufacturing parts are compulsory in a machine shop. This adjustment is because mishandling the solid block or metal parts during the CNC machining process causes wrong cuts and can increase the resistance between tools and machined parts.

It causes a poor surface finish of the resulting custom CNC machined parts instead of the right machining process.


The only solution for the above problem is the appropriate handling of the metal parts during machining and drilling. 

Problem-4 Milling and turning tools break down easily in CNC Milling

Inadequate chip evacuation:

The main reason behind the CNC mills and CNC drills tool breakage is the inadequate evacuation of the chips during the CNC drilling and milling service. Chips are necessarily produced during the CNC drilling.

But, if the excessive chip production is not handled properly, they start accumulating. The accumulation of the chips increases the resistance and ultimately causes tool breakage. The machining process continues even after the tool breakage and can cause a poor surface finish. 


The regular removal of the clips can prevent cutting tools’ breakage during machining. Moreover, use a lubricant or a coolant for proper tool functioning. 

The workpiece may not be clamped properly:

The tool breakage may occur when the workpiece is not clamped firmly during the CNC machining service. This breakage causes additional movements during the CNC milling and drilling machining process. These additional movements mainly break the corresponding tools by damaging their sharp edges. 


If the workpiece is fastened and the drill clamped firmly, it can lower the chances of tool breakage. 

Incorrect feed and speed rate for CNC machined parts:

The incorrect speed and the feed rate of the machining process during CNC milling and drilling is the primary cause of the breakage of the tool. The tools cannot properly function because of an incorrect rate of machining speed and feed.  


You must adjust the correct speed and feed rate during the CNC drilling and milling. For this purpose, carefully check the cutting speed table and adjust it accordingly. 

High temperature during drilling and milling:

If the machining tools can continue functioning without being stopped, it may cause increased temperature during CNC drilling and milling. The increased temperature may cause the breakage of the tool.


Control the temperature and provide a cool machining environment by providing lubricants and coolants. They will decrease the temperature and prevent the cutting tools from breaking, leading to a high-quality surface finish.  


The custom CNC machined parts show high precision, tight tolerances, and greater corrosion and wear resistance. During custom CNC machining, we may face machining problems that can affect the resulting custom CNC machining parts, e.g., the poor surface finish of metal or steel parts. From the above article,we know there are many reasons caused in custom cnc machining process, and also our engineers give you more solutions, hope this could help yuo improve your machining ability.

Worthy Hardware is a CNC manufacturing and sheet metal fabrication company,including CNC machining services,CNC milling services, CNC turning services, laser cutting services and stamping services.Call us +86-76989919645 or email us [email protected] for more discounts for your projects.