When it comes to setting costs in CNC machining, there exists no universally accepted cost plan for machining projects. The cost of machining projects is largely determined by varieties of factors. While cost is a vital thing to consider in a majority of the projects out there, it is important to understand the background and how it comes into play in affecting CNC machining costs.
Due to the aforementioned, we have deemed it fit to look into this contemporary issue in the world of CNC machining. Here is the most comprehensive information that will guide you on how to calculate your CNC machining in ensuring cost reduction.
Factors That Determine Machining Cost
In the CNC machining industry, one part A may be significantly more expensive in comparison with another part B. While part B may be smaller than part A, it may be more expensive compared to part A which Is larger. This shows that pricing is not solely dependent on size in CNC machining. It Is mostly dependent on a combination of different factors including;
√ Material Types
The type of materials for a particular project can greatly affect the pricing of end products. This generally affects CNC machining pricing in two ways which are the cost of processing time and the cost of raw materials. The price of the material used is dependent on the material’s value and how rare the material is. Metal materials (such as aluminum, stainless steel, brass, & copper) and plastic materials (ABS, Nylon, PEEK, PVC, PC, Delrin) all have varying prices as material types.
The effect is that materials that are hard in characteristics are more expensive to manufacture compared to others because of poor machinability. Also, more expensive material types may be durable with better performance. CNC machining engineers may decide to go for ABS & Aluminum because of high machinability while stainless steel & titanium are harder to process.
√ Cost of Labour
Once CNC machining is set up, it requires almost no human intervention. Irrespective of the situation, a programmer, machinist, and engineer is required. For programming, a programmer helps to converts a CAD file into a CAM file while some AutoCAD technology can help to automatically program the toolpath. This has greatly reduced the reliance on humans for such steps.
A machinist will help to set up the machines for production in processes like cutting the billet, loading, and many more. In this case, the cost depends on quantity and complexity. Another factor here is quality control and post-processing and it varies from industries to another. All these factors play a major role in determining the cost of CNC machining.
√ Quantity of Machined Parts
In this case, the number of machined parts can greatly affect the cost of CNC machining. The assumption is the larger the quantity the larger the overall cost of CNC machining. However, each unit added will be cheaper. This means that larger order volumes will increase overall cost while the price per unit is reduced.
A workpiece requires the same number of operations and steps as having multiple workpieces. The implication of this is that a single part is cheap but more expensive compared to when many of the same parts are produced.
√ Type of Equipment Required
Another factor that influences the cost of CNC machining is the type of equipment, tools, or machines you are to use for production. Machines used today are quite expensive. An example of such a machine is the 5-axis machining centers that offer multiple functions for complex parts.
The idea is that the simpler the machines to be used the less costly the unit time. This is evident because the cost of ordinary CNC lathe production is lesser than vertical CNC lathe production while the CNC machining center is more expensive compare to a milling machine.
√ Parts Design & Parts Geometry
Parts designs and geometry are factors that will affect the cost of CNC machining in many aspects. The idea here is that the bigger the part size the more the needed materials during the process of manufacturing. This, in turn, leads to an increase in the cost of production. In considering the complexity of parts, if the parts’ design is complex then the machining process becomes more difficult.
This will result in an increased production cycle and an increase in cost by using more suitable equipment that can handle such complex structures. On the other hand, the designs with simple features are easy to work with and save production time.
√ Tolerance Type & Precision Type
The type of precision and tolerance in CNC machining is proportional to cost or price. In CNC machining space, the required part does not need to feature unique tight tolerances unless it is required for specific situations. What is required is that drawing of parts must be importantly based on the production function.
Mostly, tight part tolerance is needed in situations where parts interfaces with one another. It is important to know that tight tolerances are somehow difficult to achieve on the part’s internal surface. Also, machining cavities and holes may develop burrs in tight tolerance and may be time-consuming to remove.
√ Other Processes (Treatment & Finishing Processes)
Some other factors or processes affect the cost of CNC machinings such as treatment & finishing, external factors such as tax charges on specific materials, shipping cost, management expenses, and many more miscellaneous expenses.
How to Minimize The CNC Machining Cost
Once we have been able to identify the major factors that affect the cost of machining, it is important to take a look at helpful and practical ways to minimize the cost of CNC machining.
√ Material Reconsideration
The use of material for your project is a huge determinant factor in determining the cost of your CNC machining parts. In this, two things come into play and are very important including the type of materials before you choose it for production and the machinability of such material. Material selection should be done based on parts application to reduce cost. Easily machined materials will also help to reduce cost and time of production.
√ Order Large Part Quantities
The cost of production per unit for a set of parts that are identical decreases with large orders. This is due to the elimination of repeated set-up costs. The CAM preparation, CAD preparation, and machine setup are done once for all parts to be produced. As a result, the cost of production is reduced.
√ Design Optimization
To reduce cost through design optimization, the following question must be asked. Did I optimize my parts using designing machinability guidelines? Can I simplify or remove any unnecessary features and still retain full functionality? Can I split my design into multiple parts and assemble it later? are there more machinable or less expensive materials that can fulfill the design requirement? While these questions are necessary for design optimization, they will also help to reduce your cost.
Try to Split Up Complex Parts
Complex parts including intricate geometries where repositioning or rotating are needed, will involve the use of custom fixtures, manual rotation or repositioning, or use of multi-axis CNC machining. All this will add more to the cost of CNC machining. The cost can be reduced by splitting up your part into two ore more easily machinable geometries if less complex designs are not achievable. What is required is to assemble them later to create your part.
Rounded Internal Corners
Parts with 90-degree corners are hard to machine. To machine such corners, the machine has to stop for the part to be rotated while after rotation machining continues. These additional steps take much time which increases time with additional cost. To solve this, you should consider changing the internal corner designs of parts to reduce the overall cost of production. This involves the use of rounded corner designs. This will allow the machine to run continuously to create parts with decreased cost of production
Deep-pocket Should Be Avoided
The use of deep pockets can greatly influence the cost of CNC machining parts. This is because deep pockets require the removal of a lot of materials. To remove material is not an easy task, it is time-consuming, and it involves the use of special tools to remove the materials to the desired depth.
In a bid to reduce the cost of production, you should consider limiting the depth of pockets to about four times the length of the part.
To reduce the cost of CNC machining, you can leverage standard drill sizes. This can be done by following the tap size and drill bit size chart. This will help to determine your type of machine and also to reconsider what amendment is to be done to pick less expensive equipment.
Thin Wall Expansion
Another way to reduce cost is through the expansion of thin walls. Thin walls are difficult and time-consuming because they are fragile. They are machined through repeated passes using low setting depth to reduce fractures or errors. To reduce your cost, use thick walls for stability.
The inclusion of tight tolerances drives up the cost because it increases the time of machining with lots of manual inspection. So it is generally hard to achieve on the internal surface because it can cause burrs on the cavity edges. If burrs occur it is an additional step beyond the manual inspection. As a result, it must be avoided as much as possible. To solve this, try as much as possible to limit the use of tight tolerances.
√ Need Outsourcing
To minimize cost, you can consider outsourcing your project to another company. While companies domiciled in developed countries offer an expensive quotation, companies in China offer less and cheaper price ranges. An example is our company, we offer a less expensive price range and we’ll take you through the process of minimizing your cost for you.
How Does Our Factory Calculate The Price
Here at RapidDone, we offer a unique quoting process that is different from any quoting from our competitors. Our unique pricing technique will help you calculate your CNC machining project cheaply and effectively. We offer two forms of pricing including prototyping & low volume as well as high volume-based pricing.
Prototyping & Low Volume Pricing
For all projects involving prototyping and low volume, we offer a fixed hourly rate of about 10-20$ per hour. Which is considerably low in comparison with our competitors in the CNC machining space. For more information on this, you can contact us or request a quote for your projects.
High Volume Pricing
If your project involves a high volume production, you can opt-in for our high volume pricing option. This is less expensive in comparison with the low-volume pricing. As we mentioned earlier, high-volume pricing is less expensive because it requires doing multiple operations at a time. Base on our experience we offer a cheap rate of $8 per hour.
Once you follow our tips in reducing the cost of CNC machining, then your CNC machining projects will be affordable. At our on-demand manufacturing company here in China, we offer more affordable deals that will help you ensure minimal spending on your project in comparison to what our competitors will offer you. You check more for our CNC machining service here, contact us today for your instant quote!