In today’s world, CNC machining has been widely used in all walks of life and is the most cost-effective production method, without any mold costs, high processing efficiency, and fast shipping, but due to various factors involved, when customers choose CNC machining suppliers, usually they do not know how to calculate CNC machining costs.
Are you also confused about the above-mentioned questions and don’t know how to calculate the cost of purchasing CNC machining?
Next, we will tell you in detail the calculation of CNC machining cost combined with comprehensive factors such as workshop machinery loss cost, raw material cost, surface treatment cost, and so on.
And I’ll give you helpful tips and guidelines on how to reduce costs within your budget.
Read on for more information on your future CNC machining cost of CNC machined parts.
When calculating the cost of CNC machining, the first consideration is the cost of raw materials.
Since the raw materials suitable for CNC machining are various, the metal includes aluminum machining, stainless steel machining, titanium machining, alloy steel, brass machining, etc., and the plastic includes ABS, nylon, POM, PEEK, etc.
Next, I will tell you the price per kilogram of common CNC machining parts raw materials.
Aluminum is the most common material in CNC machining and is widely used because it is economical, has good machinability, and is easier to post-surface treatment.
There are also many grades of aluminum. 6061 and 7075 are commonly used in CNC processing. At present, the raw material price of an aluminum plate of grade 6061 in the United States is about 5-5.5 US dollars per kilogram, and the price of raw material of aluminum rod of 6061 grade is about 4.8-5.2 US dollars per kilogram.
In comparison, the price of raw materials in China will be slightly lower. At present, the price of raw materials for 6061 grades of aluminum sheets in China is about 3.5-4 US dollars per kilogram, and the price of 6061 grades of aluminum rods is about 3.2-3.8 US dollars per kilogram.
7075-grade aluminum is more expensive than 6061 because 7075 aluminum is more suitable for aviation, ordnance, and other products that require slightly higher material strength.
At present, the raw material price of 7075-grade aluminum plates in the United States is about 6.5-7 US dollars per kilogram, and the price of 7075-grade aluminum rod raw material is about 5.6-6.8 US dollars per kilogram.
The same Chinese 7075 raw materials are also lower than those in the United States. At present, the price of 7075 aluminum plate raw materials in China is about 5.5-6.5 US dollars per kilogram and the 7075 aluminum bar raw material price per kilogram is about 5.2-6 US dollars per kilogram.
You have just learned about the approximate price of aluminum through my above, and then I will explain another material for you, stainless steel.
Stainless steel can be seen in all aspects of our lives. Of course, it is also frequently used in CNC machining. The common grades of stainless steel are 303.304.316 and so on.
The price of stainless steel 303 per kilogram in the United States is about 4.3-4.8 US dollars, and the price of stainless steel 303 per kilogram in China is about 2.9-3.5 US dollars.
The price of stainless steel 304 per kilogram in the United States is about 4.5-5.2 US dollars, and the price of stainless steel 304 per kilogram in China is about 3.2-4.1 US dollars.
The price of stainless steel 316 per kilogram in the United States is about 4.8-5.5 US dollars, and the price of stainless steel 316 per kilogram in China is about 4.4-5.3-2 US dollars.
Therefore, by comparing the prices of three common stainless steel raw materials, we can find that China’s stainless steel materials are also a little lower than the United States.
ABS or Acrylonitrile Butadiene Styrene is a common thermoplastic polymer commonly used for injection molding and CNC machining, and due to its lower hardness and shorter machining time, the plastic is cheaper for CNC machining.
Because of various factors such as density and hardness, ABS material is of course cheaper than metal.
The price of ABS material per kilogram in the United States is about 20-35 US dollars.
The price of ABS material per kilogram in China is about 9-15 US dollars.
From this point of view, not only metals but also materials in China, including plastics, will be cheaper than those in the United States.
In the past, China relied on imported materials, but now China can produce most of the materials itself, so this is one of the reasons why China’s materials are lower than those of the United States.
Above we have illustrated three material costs. In fact, there are many materials that can be processed in CNC machining.
For more material costs send an email to get a material cost list.
Machining Costs And Wear Costs
The machining cost mainly depends on the machining time required for the production of the part. The longer the machining time, the higher the cost, and vice versa.
So how can you have an evaluation of the parts you need?
How can engineers and designers reasonably reduce the manufacturing cost of parts in the design process?
Here, Yijin Hardware will answer you in detail. First of all, if you want to understand the cost of CNC machining, you must know the principles of CNC machining. CNC machining is traditional subtractive machining.
As the name implies, the surface of the raw material is cut by a piece of raw material through a tool, and the tool subtracts the surface of the raw material layer by layer until you get the part shape you need.
The time taken by this entire process is added to your processing cost.
The following is the charging standard of our CNC machining in China and CNC machining in European and American countries.
|CNC four axis||12$-18$/hours||43$-75$/hours|
To help customers, our engineering designers will have an accurate reference early in part design.
1. Processing Aging of Different Materials
There are many types of materials that can be processed by CNC machining. Commonly used are copper, aluminum, stainless steel, and plastics.
These materials have different cutting properties which also means that the processing time is different.
Among these materials, they are reflected in the processing process. The resulting cutting transitions have their own advantages and disadvantages, such as high hardness, ease of sticking to the knife, ease of deforming, and ease of shrinking.
Copper: Copper has good thermal conductivity, low strength and hardness, good plasticity, and good toughness. From the perspective of processing, there is no special difficulty in copper processing. The key is to solve the problems of sticking and breaking chips. Copper is a free-cutting material.
Aluminum: The thermal conductivity of aluminum is second only to that of copper, with high strength, good plasticity, and good cutting performance;
Steel: The cutting performance of steel is generally worse than that of copper and aluminum, especially stainless steel has low thermal conductivity and serious work hardening;
Plastic: The thermal conductivity of plastic is relatively low, but the cutting efficiency is the highest. Compared with metal cutting, the cutting force of plastic is the smallest, and the roughing is usually cut with one knife to the end.
If the same part is subjected to cutting experiments using copper, aluminum, steel, and plastic, the order of processing aging from fast to slow is plastic>copper>aluminum>steel.
2. Processing time of different production processes
CNC machining is a high-precision machining method, which is suitable for large and small batch production.
However, there are many kinds of CNC machining equipment, which are usually distinguished by machining accuracy, machining capacity, and machining efficiency.
When we need to produce a part, we will analyze the processing difficulty of the part, what kind of process flow, and what kind of equipment is used for processing can ensure the processing quality, control cost, and delivery time.
Decisions are usually made based on the accuracy, quantity, size, number of machining angles, and technical requirements of the parts.
The following Yijin Hardware will give you a brief introduction to the past processing cases:
Case 1: From European and American countries – propeller parts
Component Purpose: The main booster slurry used in underwater boosters is the core component of the product.
Surface treatment: Black anodizing
Quantity: 20pcs and 1000pcs
The working principle of the propeller is the core component that drives the propeller to rotate at high speed through the output torque of the motor.
According to the accuracy grades S, Ⅰ, Ⅱ, and Ⅲ, the part belongs to the S-grade precision. Most of the parts are curved surfaces and the processing changes are various.
After analysis, it is suitable for 4-axis CNC machining or 5-axis simultaneous CNC machining.
Because the flexibility of 4-axis CNC is not as high as that of 5-axis, there may be tool interference or incomplete cutting during machining.
Due to the rigor of the accuracy of the part, we chose 5-axis CNC machining to complete the part for 20pcs, 80$/piece.
In mass production of 1000pcs, we added a process, considering the processing cost of 5-axis linkage is more expensive at 200-300/h.
It turns out that we use solid round bars for cutting. This method has a relatively large amount of roughing and also causes a lot of material waste.
This time, we replaced rough machining with casting and only needed to finish the surface of the propeller in the 5-axis CNC machining process.
Finally, the batch processing was completed at the processing cost of 15$/piece.
3. Aging Affected by Tool Paths
The tool machining path refers to the motion trajectory of the tool relative to the machined part during the machining process.
That is, the tool starts to move from the tool setting point until it returns to this point and ends the path passed by the machining program, including the path of cutting machining and the non-cutting idle travel such as tool introduction and return.
The same processing area may also have different processing paths or more time-saving paths.
This depends on the technical level of the programmer. Yijin Hardware has 30 years of technical accumulation of top programming technology.
The following are three different machining paths, Figure 1 is dynamic milling, also known as side milling
The chips produced by dynamic milling are relatively thin. Under the action of the high-speed rotating tool, most of the cutting heat is taken away by the chips flowing out at high speed before it can be transferred to the workpiece, thereby greatly increasing the service life of the tool and saving processing time, especially when the application is quite beneficial in mass production;
Fig. 2 and Fig. 3 are similar to the cutting tool that is close to full range. It is divided into multi-layer cutting. The roughing time is short, but the heat dissipation is not good, which affects the service life of the tool and is easy to squeeze and break the tool.
The aging of the following three processing paths is Figure 1: 2min, Figure 2: 4min, and Figure 3: 5min.
- The precision machined parts should obtain good machining accuracy and surface quality (such as low roughness), and high efficiency.
- Make numerical calculation easy to reduce programming workload.
- Try to make the tool path as short as possible, which can not only reduce the number of program segments but also reduce the time of the empty tool.
Ways To Reduce CNC Machining Costs
To begin with, let us learn more about Why Are CNC Parts So Expensive? The Factors Behind Their Cost
Usually, when a new part is born, the cost of CNC machining will be high, especially in small batch production, you can optimize the part for the following three points.
1. Material Selection
The choice of material is one of the biggest factors affecting the cost of CNC machining. First of all, we should meet the needs of the product and choose materials with cheaper prices.
In addition, the machinability of the material is also important because it directly affects the machining speed and therefore the price.
2. Optimize the Design
The complexity of the machined part design determines the length of the processing time. In order to reduce the complexity of part processing as much as possible, it can be designed according to the following viewpoints.
- Try to delete some unnecessary features of the parts, and use more unified features, which can reduce the number of tools used, and at the same time can simplify the processing program and improve the processing efficiency.
- Minimize the machining angle of the parts, because this will mean an increase in the number of tooling, thus prolonging the production cycle or requiring the use of multi-axis machining machines, but this means that the production cost will increase with it.
- For some features with low precision requirements, relaxing the requirements is conducive to reducing the defect rate of parts.
3. Surface Treatment
Choose an affordable finish based on part accuracy, appearance needs, and usage environment.