Prototyping for automation and industrial engineering: choosing the right manufacturing process

Automation and industrial engineering projects put very different demands on prototype parts.

A housing may simply need to confirm fit around a sensor. A robotic gripper needs to interact reliably with a component. A jig or fixture may be used hundreds of times on a production line. A machined bracket might need to carry a load, hold a critical position or become part of the finished machine.

Choosing the right manufacturing process therefore starts with a simple question:

What does the part actually need to do?

For automation and industrial engineering applications, SLS 3D printing, CNC machining, SLA, PSLA, vacuum casting and injection moulding can all have a role. The best option depends on the stage of development, geometry, material requirements, quantity and how the component will be used.

This guide looks at where each process fits.

What is the best prototyping process for automation equipment?

There is no single best process for automation prototypes.

As a general guide:

SLS 3D printing is particularly useful for durable polymer parts, complex geometry, jigs, fixtures, housings and robotic tooling.
CNC machining is often the right choice for metal parts, engineering plastics, critical mechanical interfaces and components that need production-representative material properties.
SLA and PSLA are useful where fine detail, surface quality or accurate form and fit are important.
Vacuum casting works well when several copies of a polyurethane component are required without committing to production tooling.
Injection moulding becomes relevant when a plastic component is moving towards repeatable low-volume or production manufacture.

The process can also change as the project progresses. A component initially produced using SLS may later be CNC machined or injection moulded once the geometry, material and required quantities are established.

Start with the purpose of the prototype

The word “prototype” covers everything from a basic shape model to a component running inside a working production machine.

Before selecting a manufacturing method, establish what you need to learn from the part.

Is it for a fit check?

If the main requirement is to check dimensions, clearances, cable routing or the position of components within an assembly, 3D printing is often the most economical starting point.

SLA is particularly useful where good surface quality and dimensional detail are important.

SLS can be more appropriate where the part also needs to withstand handling or repeated assembly.

Is it a functional prototype?

Functional parts need more careful consideration.

A robotic gripper finger, locating fixture, or moving machine component may experience repeated loads, impact, abrasion or temperature changes. Material behaviour becomes more important than appearance.

SLS and CNC machining are therefore commonly used for functional engineering prototypes.

Will it become part of the machine?

Some “prototype” parts never get replaced.

A component initially produced to prove a design may perform well enough to stay on a machine or become the basis of an ongoing low-volume requirement.

In that situation, it makes sense to consider repeatability, replacement requirements and the likely production route from the beginning.

SLS 3D printing for functional automation parts

Selective Laser Sintering uses a laser to fuse layers of polymer powder. Because the surrounding powder supports the part during manufacture, SLS can produce complicated geometry without separate support structures.

That makes it particularly useful in automation and industrial engineering.

Typical applications include:

Robotic grippers and gripper fingers
End-of-arm tooling components
Jigs and fixtures
Positioning nests
Sensor brackets
Cable guides
Machine housings
Conveyor components
Assembly aids
Vacuum manifolds and parts containing internal passages

Prototype Projects uses PA 2200 CarbonReduced, a white PA12 material offering high strength, stiffness, abrasion resistance and long-term dimensional stability.

Why choose SLS?

One of the main advantages of SLS is design freedom.

Features that might require several machined components can sometimes be combined into a single printed part. Internal channels, curved forms, cable routing features and complex mounting geometry can all be incorporated into the design.

This can make SLS particularly useful for robotic tooling and special-purpose machinery where components are often designed around the equipment rather than around a standard catalogue part.

It also avoids conventional tooling, so design changes can be introduced simply by changing the CAD model.

When might SLS not be suitable?

SLS should not automatically replace a machined component simply because it can be printed.

If the application requires very tight tolerances, a particular metal, high structural loads or material properties that PA12 cannot provide, CNC machining may be more appropriate.

The actual operating environment should always drive the decision.

CNC machining for demanding functional parts

CNC machining removes material from a solid block of metal or engineering plastic.

For industrial applications, its major advantages are material choice, dimensional accuracy and predictable mechanical properties.

Typical automation applications include:

Mounting brackets and plates
Jigs and fixtures
Bearing housings
Actuator mounts
Tooling components
Bushes and spacers
Machine components
Test equipment
Mechanical interfaces
Low-volume production parts

Prototype Projects machines metals including aluminium 6082 and stainless steels 304 and 316, alongside engineering plastics including acetal.

When should you choose CNC machining?

CNC is particularly valuable when the prototype needs to behave like a conventionally manufactured engineering component.

For example, if the production part will ultimately be aluminium, testing an aluminium CNC prototype can provide more useful information than testing a polymer 3D print.

CNC machining is also useful where specific dimensions, bores, holes, threads or mating features are important.

CNC machining does not have to stop at prototyping

For automation businesses and special-purpose machine builders, volumes are often relatively low.

A component may be needed in batches of ten, fifty or a few hundred rather than tens of thousands.

In these situations, CNC low-volume production can remain the manufacturing method for the finished component. It avoids dedicated tooling and makes future design changes easier to accommodate.

SLA for housings, covers and detailed components

Stereolithography creates resin parts with fine detail and a smooth surface.

For industrial projects, it’s particularly useful for:

Machine covers
Control housings
Large enclosures
Sensor housings
Form and fit models
Components requiring a high-quality painted finish
Transparent parts where a clear resin is appropriate

Prototype Projects’ large-format SLA capability also allows substantial components and enclosures to be produced without splitting them into numerous smaller sections.

SLA is generally more suited to dimensional, visual and assembly evaluation than heavily loaded mechanical components.

If the part must operate under significant mechanical stress, SLS or CNC machining may offer a better route.

PSLA for fast, detailed engineering parts

Projection Stereolithography, or PSLA, cures an entire layer of resin at once rather than tracing each layer individually.

It combines good surface quality with fast production and is useful for detailed functional components, housings, connectors and shorter production runs.

The current PRO-BLK 10 material offers high stiffness, thermal resistance and good repeatability.

PSLA can therefore sit between visual prototyping and short-run functional production for suitable applications.

Vacuum casting when you need several copies

Sometimes the challenge isn’t producing one prototype, but producing ten, twenty or fifty similar parts.

Vacuum casting uses silicone moulds and polyurethane resin to replicate a master pattern. Different polyurethane grades can reproduce characteristics ranging from soft elastomers to rigid engineering plastics.

It can be useful for:

Small batches of machine housings
Flexible covers or protective components
Handles and grips
Seals and soft components
Multiple test samples
Pre-production components
Parts that will eventually be injection moulded

Vacuum casting is particularly helpful when tooling would be premature, but a single 3D-printed component is no longer enough.

Injection moulding for repeatable production parts

Once a design has stabilised and demand becomes repeatable, injection moulding may become the better option.

Prototype Projects produces tooling in the UK and offers low-volume injection moulding in production-grade thermoplastics including PP, ABS, PA6 and polycarbonate, with glass-filled and flame-retardant options available where required.

It’s particularly relevant when:

The component has moved beyond prototype stage
Production material is required
Consistency between parts matters
Repeat batches are expected
Quantities justify the tooling investment
A pilot or bridge-production run is required

For automation businesses producing specialist equipment in relatively small quantities, low-volume injection moulding can provide a route to production-quality components without moving straight to very high-volume tooling.

SLS or CNC machining: which is better for a jig or fixture?

Both can work well.

Choose SLS when:

Geometry’s complicated
Weight reduction would be useful
The fixture is relatively lightly loaded
You want to combine several features into one component
Designs are likely to change
Fast replacement from CAD is valuable

Choose CNC machining when:

Higher loads are involved
Metal is required
Critical interfaces need tighter tolerances
Wear resistance is important
The fixture forms part of a machining or high-force operation

Hybrid approaches are also possible. A fixture might combine a machined metal base with replaceable SLS nests or contact components.

There’s no rule saying the entire assembly has to use the same manufacturing process.

How should you choose a process for an automation component?

The most useful information to provide at the quoting stage isn’t simply the CAD file.

Explain:

What the part does
Whether it is a prototype or end-use component
Expected quantities
Loads or repeated stresses
Required material properties
Temperature or environmental requirements
Important dimensions and tolerances
Whether the design is likely to change
When the parts are needed

This gives the manufacturing team much more information to work with when recommending a process or material.

Can one supplier support the whole development process?

Using several manufacturing technologies through one supplier can be particularly valuable for automation projects because the best process often changes during development.

An SLS component may prove a concept.

A CNC version might then be produced for more demanding mechanical testing.

A batch of CNC components could support early machine builds.

If volumes increase, an injection mould tool may eventually become commercially worthwhile.

Working with a supplier that offers several processes means manufacturing decisions can follow the needs of the project rather than being dictated by the capability of a single technology.

Prototyping support for automation and industrial engineering

We support automation engineers, machine builders and industrial equipment manufacturers from our facility in Royston, Hertfordshire.

Our capabilities include SLS, SLA, PSLA and DLP 3D printing, CNC milling and turning, vacuum casting, injection moulding, model making and finishing.

Whether you need a single functional component, a jig or fixture, a set of robotic tooling parts or an ongoing low-volume supply, talk to our team about what the part needs to achieve.

Call 01763 249760, email office@prototypeprojects.com, or request a quote.