Metal and plastic parts CNC machined for heat sinks.
Prototype parts delivered in 2 weeks.
Custom metal prototypes are generally manufactured by means of CNC machining or by additive manufacture.
CNC machining offers the greatest range of material options and the best potential accuracy, but is limited by cutter reach and geometry. However, more and more we are pushing CNC to its limits with incredible results – it may be a traditional process, but it’s certainly not antiquated!
As rapid prototyping is becoming more popular, Direct Metal Laser Sintering (DMLS) is gaining ground as parts start to be designed exclusively for this process. DMLS is best suited to highly complex, small parts.
Before we go any further, be aware that in most instances metal prototyping is going to cost more than producing the equivalent part in plastic. So, the first question has to be, does it really have to be metal? Does the application warrant the additional cost? There are alternatives and it might be worth considering some of the interesting RP applications/materials out there, such as metal coated Stereolithography.
If metal is a definite, it is useful to determine whether a specific material is being sought, or whether a generic metal will do, as this again can have huge cost implications.
Most metal prototypes are in aluminium or stainless steel, however DMLS offers options such as Cobalt Chrome, Inconel and Titanium. Constraining the material to a particular grade or standard is likely to have a significant impact on the process options as flexibility is linked to the application.
It’s not just quantity, but size and geometry that will certainly influence the process choice. Complexity is “free” with additive techniques whereas CNC has to factor in the upfront programming time and fixturing required. Conversely whilst additive metal machines are getting larger, size remains a major cost driver, leading to CNC frequently winning for large parts.
The complexity is “free” comment does need quantifying. This assumes the design does not invoke support structures. If it does, then the removal of these structures can add cost.
(You may want to read our article, CNC vs DMLS for more info).
Whilst casting might be seen as “old technology” it too has embraced additive technologies. It is possible to print sand cores for sand casting and to print “waxes” for investment casting. Slightly more unconventional but very practical is to print tooling for conventional wax injection and subsequent casting.
Casting will therefore have some upfront costs that need to be addressed, but once these are taken care of, the unit price can be attractive.
Although casting can be an option, if I’m honest, we much prefer to machine. We find the high level of accuracy and the surface finishes that are available, continue to make cnc machining a more attractive single stage process. (so long as the geometry permits!)
Then there is die casting! Usually perceived as a high volume production option, by sourcing globally, we have the experience and supplier capabilities to make this process economic for lower volume production quantities. If this is of interest, give us a call to discuss potential low volume die cast options.
There are examples of high cosmetic CNC machined prototypes, DMLS and die cast parts on our gallery page or please contact us for further information or a quote. As an ISO:9001:2015 Quality System certified supplier, we can supply the perfect solution for your metal part.
The benefits of CNC parts include substantial flexibility in material choice, high accuracy and repeatability.
DMLS (or Laser Cusing) is an additive process, suitable for prototyping & manufacturing of metal parts with highly complex or feature rich designs.
Usually only associated with high volumes, Plunkett Associates can offer die casting as a low volume technique as well.