6 dicas para reduzir custos de prototipagem CNC

6 Tips to Reduce CNC Prototyping Costs

CNC Prototyping Cost Feature Image

Despite all the advances in modern technology, the cost of CNC prototypes is not low and that is understandable. After all, it requires highly qualified specialists, professional equipment and sometimes the use of expensive alloys. Carrying out prototype production in the design phase can significantly reduce the overall cost of the CNC prototype project.

What do CNC prototyping costs consist of?

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To understand how to reduce prototype processing costs, let's first look at the list of main expenses.

  1. Bulk metal . The basic principle of custom CNC machining is that you first need a large piece of metal to cut. In the prototype and small batch industries, these pumps, or blanks as they are commonly called, are actually much larger than the total mass of the final part (in some cases up to 5 times larger). This is why choosing the right alloy is important, as you are paying 3 to 4 times the mass of your piece.
  2. Setup time . Once the technical drawing reaches the CNC service, a preparatory phase inevitably follows in which processing equipment is prepared, NC programs are written and tools are manufactured or assembled. This time it is
  3. Processing time . Once preparations are complete, processing begins. The most important parameter in CNC rapid prototyping is the total time required for the process. This includes actual cutting time, tool changing, part loading and unloading, and the time it takes for CNC machine parts to go back and forth between machine tools if necessary. This effort is by far the biggest on the list and is absolutely necessary to reduce processing time.
  4. Extra time . In any manufacturing process, there are inevitable administrative breakdowns due to documentation, shipping, etc. These depend entirely on the manufacturer of the rapid prototyping parts, so you should make your selection carefully and ask how long he needs to complete the contract or have custom CNC parts shipped to your location.

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Now that we have analyzed all the expenses that affect the final cost of CNC rapid prototyping, we can come to a conclusion and create a list of tips that will help you reduce the cost of CNC prototyping for your project.

Tips for Reducing Prototype Costs

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Choose the metal correctly

Many beginners don't really think about the material. They use standard carbon steel or something colder like titanium or stainless steel to prevent rust. Both decisions can be right or wrong. What you must understand here is that the league price is not the deciding factor. For example, if you have a large volume to process, it is better to choose aluminum as you can process it much faster and the savings in processing time cover the additional processing costs.

Another problem is when you need a special property of the material, for example, that it resists high temperatures, but you go overboard and choose a higher quality material than possible. For example, you need 800 degrees Celsius, but you decide to use 950 degrees, a material that is much more difficult to process and much more expensive, but the additional 150 degrees is not necessary.

Add basic elements

Setup time can be reduced by adding special surfaces to the part, which can be used consistently to clamp the product prototype blank onto the machine tool. For example, if you are making a wave-shaped part, you can add two tapered holes to its faces so that the part can be attached to the swivel ends. Or if the part you want to mill is box-shaped, add a plane with two holes perpendicular to it.

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Avoid complex surfaces

Complex surfaces with high smoothness are not desirable in CNC parts if you choose rapid prototyping. The reason for this is that complex surfaces are often machined with a small ball end mill. This has an extremely small protrusion (approx. 0.1-0.05 mm) and you have to process the entire surface on one side (if it is in both directions, small protrusions are created). If the area of ​​a complex surface is large, it will take hours to complete it.

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Avoid thin walls and deep pockets

CNC prototyping requires a lot of force and friction. Cutting forces must be large to be able to cut a piece of steel or other alloy. This force doesn't just affect the cut. If the tool is dull or the cutting parameters are too large, the part itself can be easily bent. This can be neglected if the part contains a lot of metal and has high rigidity. The thinner and longer the piece, the more deformation you will notice due to cutting forces. This can be counteracted by reducing the cutting parameters, but this leads to an increase in processing time. Therefore, the machined parts of the prototype must have thicker walls.

Order a small series rather than an individual piece

If there is a possibility that you will need more than one prototype for testing, you should order a small batch immediately rather than ordering later as it is much cheaper. The machine shop only needs to set up its machine tools once instead of twice.

CNC prototype

Set precision correctly

Many designers believe that the more precise a piece is, the better it will look and the better the surface finish will be (polished and shiny pieces look cool, right?). However, high tolerances and extreme surface finishes mean that the prototype manufacturer must use grinding machines to achieve such sizes and surface finishes. And to sand the pieces, they must have a minimum hardness. And this requires heat treatment. The heat treatment takes at least a day, as the part must be heated, left there, and then cooled again. Therefore, it is preferable that the majority of surfaces are IT9 or lower, with a surface finish of Ra 3.2 or worse and only the most important surfaces have higher tolerances.

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