Machine builders need to cut lead times, deliver machines with higher throughput and reduce costs. 3D printing helps achieve all of these goals
If a machine handles injection-moulded plastic components, 3D printing is excellent for non-marking ‘contact’ parts, such as gripper fingers and nests, according to Prototype Projects. “These provide near-perfect support, because the surface geometry is so well matched.” Also, buyers of assembly systems want the flexibility to produce multiple variants, with little or no changeover time.
When a machine handles multiple variants or products, 3D printed change parts can incorporate snap fits or other features for rapid changeovers. Depending on the 3D printing technology used, they can be colour-coded and identification can be 3D printed as alphanumeric text and/or bar codes or 2D Data Matrix codes.
For highly dynamic machines, 3D printed parts can be optimised to provide the required strength and stiffness, but with minimal mass. Where cobots (collaborative robots) are used, 3D printing is invaluable for producing custom gripper jaws or end of arm tooling, so the cobots can be redeployed rapidly from task to task.
“3D printing is very cost effective for producing relatively simple components,” adds Prototype Projects. “For example, sensor brackets can be quicker and cheaper to 3D print than to buy as standard parts. Furthermore, a standard bracket might be adjustable, whereas a 3D printed bracket mounts the sensor in exactly the right position. This saves time and prevents errors during build and commissioning. It also prevents misalignment due to vibration or incorrect adjustment.”
Cabling and pneumatic lines
3D printing is excellent for bespoke attachments for cabling and pneumatic lines, stopping them from working loose during transportation to the customer’s site or due to vibration, the company adds. This avoids problems when commissioning and unnecessary warranty call-outs.
If a 3D printed part is not quite right, it is quick to amend the CAD model and manufacture a replacement. 3D printing therefore plays an important role in overcoming teething problems and reducing commissioning time.
Some 3D printing systems process elastomeric materials, which is cost-effective for custom seals and gaskets. Elastomeric parts are also ideal as buffers, vibration dampening elements and for incorporating compliance within mechanisms.
3D printing provides the opportunity to combine parts – such as a gear, cam and sensor trigger. Doing so reduces mass, simplifies the design, minimises the parts count and cuts costs.
Other possibilities include: incorporating passage within robotic end-of-arm-tooling for compressed air or vacuum; creating multi-material parts with integral elastomeric seals; vacuum grippers with rigid mounts and custom bellows; and living hinges, allowing for small movements.
Experimenting with different handling concepts
In a new product development project, before injection-moulded parts are available, the assembly system designer may need to experiment with different handling concepts. Small volumes of representative parts can be 3D printed for this purpose.
After the machine has been built, it can be tested using 3D printed parts. Once production parts are available, commissioning is quicker, because teething problems have already been resolved.
“If you are a special-purpose machine builder, the end user might have certain requirements relating to spares availability. Manufacturing parts by 3D printing can avoid the need for spares to be stocked, as parts can be made to order,” says Prototype Projects. “On the other hand, if you build, say, ten identical machines per year, parts can be 3D printed as required. This is better than ordering ten parts, paying for them all at once and holding most of them in stock.”
3D printing is not a panacea and designers need to understand not only the benefits but also the limitations and pitfalls – and how to overcome them. There are many 3D printing processes and materials today, so the right combination must be chosen with care. This ensures the part has the required strength and stiffness, as well as resistance to fatigue, elevated temperatures, moisture and fluids. In some instances, mechanical properties are enhanced with threaded inserts or other means.
For advice on 3D printing for machine builders, it is best to talk to a specialist supplier that offers a variety of 3D printing technologies so you can be sure of optimising the part design, process and material.