Since the development of the machining industry, CNC numerical control machining is a good processing method, but its processing cost is also an important factor to be considered.
Factors such as material, design, finish, quantity, and turnaround time will all affect the cost of a CNC machined part.
Before explaining how to reduce the cost of cnc machining parts, we need to understand which factors will affect the price of cnc parts:
1- Processing time:
The longer a part takes to process, the more expensive it will be. Processing time is usually the main influencing factor for cnc machined parts.
2-Material:
The prices of different raw materials are often different. Even materials with similar performance can vary widely in price.
3- Tolerance:
Tighter tolerance requirements will make it more difficult to process, and the scrap rate will increase, which will lead to higher cnc processing costs.
4- Quantity:
It takes the same programming time to produce 1 as it does to produce 1000, so if there are more quantities in the same batch, then the total cost will be spread out, reducing the cost of the individual product.
5- Surface treatment:
If surface treatments such as layering, smoothing, anodizing, and black oxidation are required, and some workpieces even require partial electroplating, partial anodizing, two-color prototype oxidation, or one area is oxidized and another area is electroplated, processing steps and processing costs will be increased.
6- Delivery time:
The short lead time means that suppliers need to coordinate more workers to arrange this batch of orders first, and have to delay processing other orders. This is also a small factor in the additional cost, referred to as the "expedited processing fee".
Here are a few proven design tips that will help you save money.
a- Choose the most suitable material
When you design a machined part, choosing the right material is the most important way to save money. It is not necessary to pursue the most expensive material, but to find the most suitable material according to the use and function of the part;
There are many materials with almost the same functions, but the prices are very different. When you use more expensive materials to achieve a certain function, you can find out whether there are other alternative materials that can meet these functions.
b-Try not to use 90° interior angle
Sharp or 90° internal corners will take more machining operations and time, and will add additional costs. However, most of the inner corners do not need 90-degree right angles, and the rounded corners do not affect the use of functions.
If your design includes rounded corners, the machine can run continuously to create your part. CNC machining tools such as milling cutters and end mills automatically leave rounded interior corners. Small or narrow fillet radii require more passes and special small tools, which will increase machining time and require tool changes at any time. In contrast, larger radii at corners mean larger tools can effectively cut the part.
For the best design, make sure the L:D (length to diameter) of the inside corner radius is 3:1 or less. Also, keeping all interior corners the same radius can reduce machining time.
c- Minimize internal cavities (deep pockets)
Metal or plastic parts with deep cavity (deep cavity) designs are often time-consuming and difficult to machine. Creating the cavity requires removal of a large amount of material, which will result in wasted material and difficult removal of cuts, or may require special processes (wire EDM or sink EDM) to achieve depth.
This will cost you more;
d-Avoid thin-wall design
Machined parts with too thin walls will take more time to machine because they will be very fragile. And since they often vibrate or deform, it can be difficult to maintain target accuracy. Slow processing and special processing techniques, high scrap rates make these thin-walled parts more expensive.
The processing of thick-walled parts is more stable and the processing cost is lower. In order to keep the processing price low, please avoid thin-walled design, and the wall thickness of metal parts should be at least greater than 0.8mm. The wall thickness of plastic parts should be greater than 1.5mm.
e- Avoid designing complex parts
Machining oversized, non-dimensional or complex designed parts requires special tooling, multi-axis CNC machines or some custom fixtures, all of which will add to the overall cost.
In some cases, if you need complex parts that operate on multiple faces, you can try to split the part into 2 or more separate parts, and then machine the shaft welded or bolted together, at this time the cost will decrease.
f- Avoid surface finishing, such as Tin coating, Dlc coating
Surface finishing of CNC machined parts is the addition of machining to achieve desired surface characteristics or properties for aesthetics, corrosion resistance, wear resistance, or other purposes. However, these surface treatments such as heat treatment, sandblasting, special coating, anodizing, etc. will increase the total cost, so it should be carefully evaluated according to the processing purpose;
If you want to lower your overall cost, you can opt for a standard machined finish; this is a quick and affordable option and is often used for non-display applications such as mounting brackets;
g- Avoid excessive use of tight tolerances
With ultra-precision processing equipment and production experience, it can meet the tolerance of precision to ±0.001mm. However, we still recommend that tight tolerances should not be overused for non-special purpose parts. Because the smaller the tolerance, the more processes and time the factory needs, which means that the price will be much higher
Not every part requires strict tolerances, except for some precision mold parts, medical parts and aerospace spare parts, the editor suggests that other parts should follow common standards, such as ISO corresponding standards, which are reasonable for cnc machining parts design of.
h-Bulk order
While modern CNC lathes and mills can run more efficiently than ever before, they still require engineers to program and set them up. Parts ordered in bulk have a great influence on the unit price. Because mass-produced identical parts maximize the productivity and cost-effectiveness of CNC machining;
I. Advance the work and prepare the production plan in advance
Develop product blueprints, advance design work, and finalize product designs before commencing production. This will allow CNC machining suppliers sufficient time to source raw materials, specify production schedules and deliver products within the agreed time.
Shenzhen Yixin Precision Metal and Plastic Ltd. is a one-stop service factory specializing in aluminum machining, anodizing and assembling. The company was established in 2004 and has long been devoted to the production of aluminum products for any industry.
