Frequently Asked Questions

What are my options for metal prototyping?

In most instances metal prototyping is going to cost more than producing the equivalent part in plastic, so our first question would be, does it really have to be metal?

We need to be confident that the application warrants the additional cost. It might be worth considering some of the interesting RP applications/materials out there, such as metal coated Stereolithography. They might be able to deliver a suitable alternative and we’d be happy to talk you through the options.

We also need to understand if a specific material is being sought, or whether a generic metal will do. 

What data do I need to provide?

We can usually quote from an stl file, but this won’t contain any surface finish, threads or tolerance information. In most instances going to metal will require a toleranced drawing with all the associated call outs. It is imperative that this is available at the time of quotation as it impacts both process selection and cost.Die Cast prototypes

From a production perspective

Most parts are designed as either CNC, Castings or Die castings in production, although as the capability of DMLS continues to improve we are starting to see some items designed especially to take advantage of layer based manufacture.

Using CNC or DMLS to prototype a part designed to be produced this way would be the obvious starting point. However we would have to take into consideration your required quantities and timescales as they will have a dramatic effect on price.

From a process perspective

DMLS is best suited to highly complex, small parts. That said, it is capable of producing some stunning parts up to the limit of the bed size (usually 250mm x 250mm although larger machines are starting to become available). At these kinds of sizes the geometry of the part will drive the decision as the premium over CNC will be significant. 

Direct Metal Laser SinteringWhen considering DMLS we must remember there will be supports that have to be removed post build. These are usually wire cut from the part or CNC machined, hence the geometry of the parts lower surface can have a big impact on this operation.

CNC machining offers the greatest range of material options and the best potential accuracy, but is limited by cutter reach and geometry. However, we continue to push CNC to its limits with incredible results. 

How does quantity affect my choices?

Your required quantities will influence the decision making process. CNC requires upfront programming time that needs to be amortised into the number of parts. Hence unit prices tend to fall initially, and then stabilise.

With DMLS, quantity is all about optimisation of platform area and part geometry. Hence just because 100 parts are required, DMLS does not have to be ruled out as a solution - assuming they can all fit in a compact area and that minimal supports are required.

DMLSIs time an issue?

Time is always a factor in assessing which route to take and available capacity will affect your time limits.

CNC machining has the biggest advantage here as it may be possible to drip feed parts, as opposed to alternative processes that require a time to manufacture tooling before part production can commence.

Material choice

When it comes to material, the level of flexibility is linked to the application. Most metal prototypes are in aluminium or stainless steel, however DMLS offers options such as Cobalt Chrome, Inconel and Titanium. If the purpose is to emulate the mechanical properties of the production part then this will require that the process be matched as well. 

Constraining the material to a particular grade or standard is likely to have a significant impact on the process options and hence time to produce the prototypes.

And finally, what affect will the geometry of the part have on my choices?CNC machined metal

Features such as thin walls, internal sharp edges, aspect ratio of the features, part size, surface finish, accuracy etc. all have a significant affect on the selection process. Internal sharp edges are the classic scenario that can add time and cost when the only reason they are on the data is that no one has thought to add a radius.

What else?

The following information will also be extremely useful in helping us find the best solution for your part:

  • Can we apply different options to different shipments? For example, can the first 10 be produced with CNC and the balance cast and post machined?
  • How critical is the material call out and how flexible can this be?
  • Have you got the correct control drawings in place to control what you purchase?
  • Do we have the flexibility to only call up tight tolerances where really required and allow some fluidity of form where it is not so important? (Note a 0.5 mm radius can make a big difference form a machining perspective!)

Allowing us early access to your requirement and the opportunity to develop the prototyping solution with you can make a huge difference in achieving a cost effective solution. Get in touch today and let’s begin looking at finding the best solution for your part.

  • “Plunkett Associates have excellent breadth of experience, work with high quality partners and have a flexibility that we have found enables challenges to be met successfully, cost effectively and in a timely manner.”
    Nick Skaer, CEO, Orthox Ltd
  • Plunkett associates always find a solution. Whatever we need to prototype, they have a great grasp on the technologies available, costs and lead-times so we get the right solution tailored to the project needs. Have always delivered and never let us down.
    Naim Audio
  • “I can’t recommend Tim and his team highly enough. We ended up with a design which can be produced and assembled quickly, efficiently and reliably, in volumes that make sense”
    Simon Leggett, Director, Olivewood Technology
  • "Tim's experience, expertise and supplier base have been fundamental to us getting this project off the ground."
    Sam Pearce, Jelly Products Ltd
  • “We were really surprised at how quickly they turned round such a high quality prototype and the parts certainly proved their worth. They were of high enough quality to provide a fantastic visual representation and to undergo rigorous testing."
    Stuart Wilson, Design Director, TRT Lighting
  • “Accuracy, finish and delivery all first class.”
    Andrew Peters, JMDA Ltd
  • “We use Plunkett Associates because we want someone we can trust, that knows what they’re talking about, has all the contacts, will provide reliable advice and feedback and will get the right result for us.”
    Jim Copestick. Design Manager, Thorlux Lighting
  • “We always know exactly what we’re getting and we know we won’t be let down on quality, price or lead times.”
    Mark Williams, Research and Development Director, Johnson Safety Products
  • “Plunkett Associates truly offer a complete turnkey solution with Speed, Effectiveness and Precision.”
    David Harden, Director, Enica Ltd
  • “Kirintec were thrilled with Plunketts. They made a complex process simple and we were just amazed at the lead times achieved. Plus, every single deadline was met without any drama.”
    Penny While, Marketing Director, Kirintec
  • “Thanks to Plunkett Associates flexible, bespoke and cost effective service I was able to produce the objects that I had originally had in mind.”
    Simon Ryder, Artist
  • To create such a consistent quality finish in chrome was an amazing achievement and the prototypes really gave our stand the wow factor.
    James Clark, Group Commercial Director, The Airdri Group
  • Interestingly, people who look at it in its own right with little knowledge of what it does, just like it! It’s tactile and it looks good…
    Tim Collings, Operations Director, Troika Systems Ltd
  • "With their simple to understand language, willingness to go the extra mile and approachability, Plunkett Associates were a great partner for our company. We couldn’t be happier with the results of our project. (A working prototype that they got right first time, by the way). Thank you!"
    Carolina Ballon-Forrester, Director, Kittyrama Ltd
  • Plunkett Associates worked on the design and production of titanium frames for an artificial heart valve where precision and consistency was paramount. Communications were efficient and productive with concepts readily incorporated into the final design, and suggestions for improvements all highly appropriate. The quality of the end product was ideal and I have no doubt that I will use the advice and expertise of Plunkett Associates again.
    David Wheatley, Wheatley Research Ltd
  • “Thanks for the present that arrived this morning, as promised. Parts look first class, as always.”
    Jon Todd, Design Manager, PHS Group
  • “Plunkett Associates have a fantastic supply chain, work with all sorts of production processes and will always do their utmost to solve a problem.”
    Naim Audio
  • “ Plunketts developed a solution that met our precision requirements at a cost significantly lower than alternative manufacturing approaches we had investigated”
    Nick Skaer, CEO, Orthox Ltd
  • “Doing business with you has been an absolute pleasure. You have made my goals a reality. You have been patient, helpful and above all, responsive. Best service that I have experienced in ages. I consider Plunkett Associates to be an integral part of my business plan moving forward.”
    Jet Cooper, Sculptor
Related Processes

CNC Machining

The benefits of CNC parts include substantial flexibility in material choice, high accuracy and repeatability.

more info

Stereolithography (SLA)

Produces accurate 3D models with a range of material choices. High Res SLA and Micro SLA for smaller parts.

more info

Direct Metal Laser Sintering (DMLS)

DMLS (or Laser Cusing) is an additive process, suitable for prototyping & manufacturing of metal parts with highly complex or feature rich designs.

more info

Sheet Metal

Sheet metal is suitable for both low and high volume applications. The higher the volume the higher the tooling costs.

more info

Investment Casting

Investment Casting produces good surface finish and accuracy for metal parts although some machining may still be required.

more info

Sand Casting

Sand Casting can create simple metal parts in 7-10 days, although post machining may be required.

more info

Read more expert articles in our FAQ section where we discuss topics on materials, methods and products.

Back to FAQs
  • “Plunkett Associates have excellent breadth of experience, work with high quality partners and have a flexibility that we have found enables challenges to be met successfully, cost effectively and in a timely manner.”
    Nick Skaer, CEO, Orthox Ltd
    Nick Skaer, CEO, Orthox Ltd
  • Plunkett associates always find a solution. Whatever we need to prototype, they have a great grasp on the technologies available, costs and lead-times so we get the right solution tailored to the project needs. Have always delivered and never let us down.
    Naim Audio
    Naim Audio
  • “I can’t recommend Tim and his team highly enough. We ended up with a design which can be produced and assembled quickly, efficiently and reliably, in volumes that make sense”
    Simon Leggett, Director, Olivewood Technology
    Simon Leggett, Director,  Olivewood Technology
  • "Tim's experience, expertise and supplier base have been fundamental to us getting this project off the ground."
    Sam Pearce, Jelly Products Ltd
    Sam Pearce, Jelly Products Ltd
  • “We were really surprised at how quickly they turned round such a high quality prototype and the parts certainly proved their worth. They were of high enough quality to provide a fantastic visual representation and to undergo rigorous testing."
    Stuart Wilson, Design Director, TRT Lighting
    Stuart Wilson, Design Director, TRT Lighting
  • “Accuracy, finish and delivery all first class.”
    Andrew Peters, JMDA Ltd
    Andrew Peters, JMDA Ltd
  • “We use Plunkett Associates because we want someone we can trust, that knows what they’re talking about, has all the contacts, will provide reliable advice and feedback and will get the right result for us.”
    Jim Copestick. Design Manager, Thorlux Lighting
    Jim Copestick. Design Manager, Thorlux Lighting
  • “We always know exactly what we’re getting and we know we won’t be let down on quality, price or lead times.”
    Mark Williams, Research and Development Director, Johnson Safety Products
    Mark Williams, Research and Development Director, Johnson Safety Products
  • “Plunkett Associates truly offer a complete turnkey solution with Speed, Effectiveness and Precision.”
    David Harden, Director, Enica Ltd
    David Harden, Director, Enica Ltd
  • “Kirintec were thrilled with Plunketts. They made a complex process simple and we were just amazed at the lead times achieved. Plus, every single deadline was met without any drama.”
    Penny While, Marketing Director, Kirintec
    Penny While, Marketing Director, Kirintec
  • “Thanks to Plunkett Associates flexible, bespoke and cost effective service I was able to produce the objects that I had originally had in mind.”
    Simon Ryder, Artist
    Simon Ryder, Artist
  • To create such a consistent quality finish in chrome was an amazing achievement and the prototypes really gave our stand the wow factor.
    James Clark, Group Commercial Director, The Airdri Group
    James Clark, Group Commercial Director, The Airdri Group
  • Interestingly, people who look at it in its own right with little knowledge of what it does, just like it! It’s tactile and it looks good…
    Tim Collings, Operations Director, Troika Systems Ltd
    Tim Collings, Operations Director, Troika Systems Ltd
  • "With their simple to understand language, willingness to go the extra mile and approachability, Plunkett Associates were a great partner for our company. We couldn’t be happier with the results of our project. (A working prototype that they got right first time, by the way). Thank you!"
    Carolina Ballon-Forrester, Director, Kittyrama Ltd
    Carolina Ballon-Forrester, Director, Kittyrama Ltd
  • Plunkett Associates worked on the design and production of titanium frames for an artificial heart valve where precision and consistency was paramount. Communications were efficient and productive with concepts readily incorporated into the final design, and suggestions for improvements all highly appropriate. The quality of the end product was ideal and I have no doubt that I will use the advice and expertise of Plunkett Associates again.
    David Wheatley, Wheatley Research Ltd
    David Wheatley, Wheatley Research Ltd
  • “Thanks for the present that arrived this morning, as promised. Parts look first class, as always.”
    Jon Todd, Design Manager, PHS Group
    Jon Todd, Design Manager, PHS Group
  • “Plunkett Associates have a fantastic supply chain, work with all sorts of production processes and will always do their utmost to solve a problem.”
    Naim Audio
    Naim Audio
  • “ Plunketts developed a solution that met our precision requirements at a cost significantly lower than alternative manufacturing approaches we had investigated”
    Nick Skaer, CEO, Orthox Ltd
    Nick Skaer, CEO, Orthox Ltd
  • “Doing business with you has been an absolute pleasure. You have made my goals a reality. You have been patient, helpful and above all, responsive. Best service that I have experienced in ages. I consider Plunkett Associates to be an integral part of my business plan moving forward.”
    Jet Cooper, Sculptor
    Jet Cooper, Sculptor