Have you ever wondered how the price for your Prototype part is determined? Then have a read as James Murphy from HLH takes you through the process that determines how suppliers arrive at your quoted price.
There are five main drivers of cost;
2. Machining or processing
3. Post processes
Materials are a tricky one. For large parts, materials are one of the main drivers, for small parts they may be so insignificant they are essentially ignored. What happens when the estimator opens your CAD file is they will measure it, xyz, then based on these dimensions plus a little extra stock on all sides will cost up a piece of material. That is your material cost. Billets of material for CNC range from around $3/kg up to over $200/kg depending on what you need.
Next is machining, this includes programming, manufacturing any fixtures and actually cutting the material. The shop will look at your part, and based on experience will estimate how long it is going to take to write the code for the machines, how long to machine it and how complex the whole thing is going to be. Then depending on the type of material, tolerances and complexity will decide what machine to use. In China, there are shops who will cut ABS plastic quickly, with little regard for tolerances, for as little as $5 an hour, and there are parts requiring high-speed 5-axis machines costing around $150/hr. Essentially as with most things in life, you get what you pay for. That said if all you need is the former then you would be silly to pay for the latter.
Post Processes include hand finishing, polishing, painting, plating and so on. Depending on the type of part you are prototyping these can either be minimal or a major diver of cost. If you are prototyping structural components where tolerances are tight and need to be right you might want to avoid having anyone touch the part after it comes off the machine. If you are making a high-quality appearance model then this is where the real work begins.
A useful example would be an appearance model of a mobile phone. Materials might be just $10, as it’s an essentially flat rectangle cuboid so there is not a great deal of machining to worry about but the finish is key and the types are many. The screen need a high gloss finish, you might have an anodized aluminium frame, it needs painting, silk printing logos and skilled handwork to assemble the camera and other components in there to make it look realistic.
Overhead is not contributing a great deal to the cost of individual prototypes as such, but it does influence the costs so we’ll take a look at it here. There is a massive range of companies making prototypes and models in China. Some are ISO certified, well-managed enterprises whose dedication to manufacturing and delivering high quality and service are going to drive costs up a little. Others are one-man shops with very little overhead to speak of. You can get good parts out of the smaller shops, but they will struggle to do it consistently.
The final driver of cost is profit, and this is as difficult to pin down as the others. Certain parts and prototypes command larger profit margins than others. Generally, highly skilled appearance models will have a higher profit margin than CNC machined structural components say. Of course traditional also rules apply, so if you make more than one, you generally pay less for each.
If you have any questions or need any help getting things made in China, happy to help firstname.lastname@example.org.
By James Murphy
At HLH, we make things for you.