CNC machines can be used to manufacture products from various materials, such as metals, alloys, and plastics. The cost of producing a product in CNC technology depends on many factors. This article discusses various factors that affect the price in CNC metal processing. This will help you calculate the costs of CNC processing and provide tips on how to reduce costs.
9 factors influencing the calculation of CNC machining costs
CNC machining costs can vary depending on the different factors discussed below:
Cost of CNC machine - CNC machining process
The costs of equipment vary depending on the type of machine. There are mainly two types of machines used for part production through CNC machining, namely three-axis machines and multi-axis machines. The cost of the machine also depends on various factors such as the size and weight of the machine, speed, power, and machine configuration. Machining costs are calculated based on an hourly rate, with an approximate cost of about 180 per hour for 3-axis CNC machining and about 150 USD per hour for a CNC lathe. The hourly rate for CNC machining on a multi-spindle machine is relatively high and ranges from 330 to 550 PLN. CNC milling is more expensive than other types of machining operations due to more complex parts. Machining costs increase with the addition of milling axes. For example, in the case of 5-axis machining, it costs more compared to a 3-axis machine.
Processing Time
The time required for full processing of each CNC machined part also plays an important role in calculating CNC machining costs. The general rule is that the more time you devote to machining, the higher the machining costs, which make up the basic retooling cost. Software such as CAM requires a 3D CAD model of the project and can estimate how much time it will take to complete the project. A very complex project requires more time.
Work
One of the advantages of CNC machining over manual machining is the reduction in the number of workers involved in production. The main labor cost is the 3D CAD model designed by experienced designers for machining, which increases with the complexity of the desired product. This cost remains the same, even if more parts need to be produced to lower the machining cost. Then, the additional cost is the labor of operating the CNC machine, which increases with the time needed to produce the part. Labor costs increase if manual work is performed for assembly, finishing, and final machining of the part. Additional labor costs are also added if the finished product is shipped from the workshop to a customer in another location.
Complexity and size of shape - complex CNC parts
As the complexity of CNC machined parts increases, so do the machining costs. More complex parts may require more stages of the process, different tooling, and longer production time. Features of parts, such as sharp internal corners, deep cavities or thin walls, increase the cost of CNC machining. Designs with simple features are easy to execute and also save production time. Larger parts require more raw materials and time to produce, so they will cost more compared to smaller parts.
Material Costs
Material costs are also necessary to calculate CNC machining costs. The price of the final product made by the CNC machine depends on the type of materials you are obliged to use for the product. You may be required to make parts from plastic or metal materials. Since plastic materials are cheaper and less durable, the cost of machining plastic or aluminum material is lower compared to stainless steel. As in CNC machines, material is removed from solid blocks. Machinists buy materials in the form of solid blocks and calculate the cost of the product per block. The most commonly used metals in CNC machining are aluminum, stainless steel, and brass. Due to the economical prices and excellent machinability of aluminum, most operators use aluminum in CNC machines. Stainless steel and brass cause higher costs due to poor machinability compared to aluminum. Titanium alloy is the most expensive of all these metals, so the cost of machining this metal will be the highest, as it may require special tools to produce parts. In the case of plastics, the price of bulk material is lower, the required tools also cost less and they require less time to process plastics, such as Nylon, Delrin, and ABS.
Surface finishing - oxidized parts
For some products, surface treatment is required, which also increases the price of the final product. Good surface treatment, such as polishing, may be required to improve aesthetics and remove any scratches that occurred during the processing. Other finishing processes may also include galvanizing, anodizing, painting, chroming, blackening, zinc plating, brushing, and water printing. Including any of these finishes adds an additional cost to the final price of the product.
Cost of Form
In some production cases, standard equipment is not useful and custom is required, which also increases the cost of production using CNC machines.
Tolerance
Costs also increase in the production of products with narrow tolerances, as complex machines are required to produce parts with narrow tolerances. Sometimes it may be necessary to make holes or recesses with narrow tolerances, which can cause burrs on the surface, and their reduction will take more time.
Quantity
The size of the order has a huge impact on the cost of the final product. It's true that the total cost increases when a larger number of finished parts is required, but the cost per part decreases.
How to save on CNC machining costs
Before starting a project, calculate the cost of your CNC machine. Minimize costs during parts production using CNC machining processes. Customers have certain fixed requirements that cannot be changed, but there are still various ways to reduce processing costs.
Quantity - small batches of CNC parts
If you need to produce parts in large quantities, you can save a lot of processing costs. The cost per part will be reduced, as you only have to design the same part once. In this case, it is necessary to repeat the machine setup for each part, which also reduces production costs.
Choose materials wisely
To reduce the cost of the product, special attention should be paid to the selection of materials. Materials with good mechanical properties will have lower processing costs. Keeping in mind the functionality of the product, choose the best available materials to ensure ease of use. There is a difference in price between plastic and metal materials. Of course, you can use your design needs as a guide and ask the manufacturer for more advice on material selection.
Project Optimization
If some features of the product do not affect its function, the project should be optimized to avoid processing these features, thereby reducing production costs.
- Consider the aperture and profile - precise CNC parts
During the production of CNC parts, it is necessary to ensure that the elements of the parts (for example, holes, contours, slots, threads, etc.) can be manufactured using commonly used standard tools. Non-standard sizes of holes and threads will require very expensive special tools. Many references to standard sizes used in the machining industry can be found on the Internet.
- The construction of parts allows to avoid thin walls and deep cavities
Thin-walled parts and deep recesses are difficult to process and often prone to dimensional errors. These features of parts often cause vibrations of the parts, and sometimes lead to the scrapping of parts.
- Whenever possible, avoid the requirement of very narrow tolerances.
Parts with narrow tolerances are harder to obtain and therefore more expensive. Only control dimensions when the overall functionality of the part requires it. One piece of advice we can offer is to design parts in such a way that they have a common reference point or reference system. This will help both you and the mechanic. Firstly, you minimize the dimensional checks that need to be carried out on the part, and secondly, the mechanic reduces the inspection time, which lowers costs.
- If complexity cannot be avoided, replace part of this complex part with a modular component.
When a part becomes too complex, it makes sense to divide the whole part into components for assembly. This makes handling easier and simpler. It significantly shortens the setup time, reduces processing operations, and optimizes processing time. This is a strategy commonly used by designers to increase the production capabilities of parts and reduce production costs.
CNC turning services, or machining, can have different price lists. It can depend on factors such as the size of the order, the type of material being processed, the surface being processed, and other issues. CNC turning can include additional operations such as oblique milling, free milling, or processing of synthetic materials. The machined surfaces can be of complex shapes, which also changes competitive prices. Many factors influence the costs. Our company guarantees that the order entrusted to us will be carried out professionally and at a good price!