Manufacturers
3D Printing and Model Making
Intro
Creating an aesthetic mock-up of a general shape or concept is useful for usability studies and marketing. This is where a model maker can help, as creating a good-looking product requires hands-on craftsmanship skills in techniques like painting and finishing.
A local model maker may also offer a rapid 3D printing service with next-day shipping, including value-add options like adding threaded inserts, applying a lacquer etc.
Manufacturers
Design tips
Choose SLA over FDM for superior accuracy and surface finish.
Machining
Intro
Chinese manufacturers tend to be very cheap and very fast (~2-week lead time), however, they occasionally see tolerances as targets rather than requirements, and it can be challenging to communicate issues if things are not made as per the drawing. That said, the quality is often pleasantly surprising given the value and fast turnaround, so it's often an option worth considering. For rapid prototyping and low-volume manufacturing, there are companies that specialise specifically in serving international customers.
Local British manufacturers tend to be more expensive and slower (~4 week lead time), however, you benefit from being able to pick up the phone to have a quick conversation, which is particularly useful if you have a job which is challenging.
Manufacturers
Chinese
British
Design tips
The typical tolerance achievable is dependent on the specific machining process. More information can be found here.
Injection Moulding
Intro
Due to the complexity of injection moulding, even after following best practices, there will likely be non-conformities which need to be addressed through iterations in collaboration with the moulder. The process usually involves:
- The moulder performing a preliminary analysis before machining the mould tool, the findings of which will be summarised in a 'Design for Manufacture' report which will:
- Describe the mould tool design to help you identify potential locations of artefacts due to gates, parting lines, weld lines, ejector pin marks etc.
- Highlight any concerns regarding wall thickness and draft and suggest solutions.
- Highlight any challenging tolerances on your drawings.
- They may also include a 'part may deform' note, with a few arrows showing how the part may warp in a few directions, just to cover themselves!
- Review the report and reply, explaining what recommendations you have and haven't accepted, and why.
- The moulder will then machine the tool and run tool trials. On completion of a trial, you should expect a sample of parts together with a dimensional report. The more complex the part, the greater the number of iterations that might be required to arrive at an acceptable part.
Manufacturers
Injection moulding
Micro injection moulding
Design tips
- Review the injection moulding design resources here.
- Aim for a uniform wall thickness and 1° draft angle.
- Take a 'metal-safe' design approach, as it is relatively easy to remove metal from a mould but very difficult to add it. This might maximise the clearances for crush ribs, snap fits etc., but it can be reduced during later tool trials if a tighter fit is required.
- Ensure important cosmetic surfaces and sealing surfaces are free from artefacts e.g. gate marks, parting lines, weld lines, ejector pin marks etc.
- If fastening parts together, use EJOT's PT self-tapping screws, following their design guide for the screw bosses.
- Detailed moulding simulations can be performed in software if additional confidence is needed, but remember that FEA software is not a be-all and end-all. It might help identify and solve a few more unforeseen problems, but ultimately it's a tool which still makes assumptions and will not be perfectly realistic. It's often worth learning what's possible directly from tool trials, unless complexity and tool modification costs are particularly prohibitive.
Contract Manufacturing and Assembly
Intro
If your moulder does not offer an assembly service, or if your device is complex, a contract manufacturer can perform the final assembly of your device so you don't have to.
Manufacturers
Collaboration tips
Follow these general steps:
- Audit candidate manufacturers to identify an appropriate one which meets your requirements (quality system, relevant qualifications, goods in/out and inventory management methods, quality control and inspection capabilities, experience in manufacturing products of similar complexity, geographic location etc.).
- Hand over the manufacturing process gradually through a series of trials. The more complex the product, the greater the level of collaboration that will be required to straighten out production issues.
- Ensure traceability of raw materials (inputs) and finished parts (outputs).
- Add visual inspections for each process step. Measure critical features, especially in areas where non-conformities persist, addressing them through corrective and preventive action techniques.
- Create a sampling plan and regularly audit the quality of parts through statistical process control.
- Evaluate the final manufacturing process by running a pilot production build and performing first article inspections.
Manufacturing brokers
These brokers are third parties with a supplier network. They post your job on a board which machine shops bid on.
Other
Ultrasonic welding
Polyurethane RIM moulding
Sheet metal
Etching
Stainless steel tubing
Frame building
Special Purpose Machinery and Automation
The intention of this page is to highlight typical manufacturing methods and to signpost a few examples for each. Many manufacturers offer a range of services, not just the ones they are categorised under. This information does not constitute an endorsement or recommendation of their services.