- The maximum part size is 490mm x 390mm x 200mm.
- The minimum feature size for PolyJet parts is 0.3mm in any direction. Unsupported walls and part features can be as small as 0.75mm across, but those serving in a functional or load-bearing manner should be at least 1.0mm across. Also, the height of these features depends partly on the material and part geometry, but try to avoid very tall freestanding walls or bosses, as these can be damaged during support removal.
- Even though PolyJet can produce fine details, bear in mind that the expected length and width dimensional tolerance is +/-0.1mm for the first inch, increasing by +/-0.001mm for each additional inch. Your “mileage” may vary, depending on the part geometry and material used.
- It’s difficult to remove support material on holes, slots, and channels much smaller than 0.75mm across, (maximum length-to-width aspect ratio of 4:1). In fact, narrow features like this might not form properly at all, so be sure to keep this in mind on part designs. Also, you might be tempted to put in some weep holes (these allow the support material to “weep” or drain out of internal cavities) on internal “land-locked” shapes, like the inside of a cube or sphere. This is fine, provided the holes are large enough to allow rinsing of the support material, but unless there’s a compelling reason to do otherwise, just leave them closed. Chances are you won’t even notice the trapped support material.
- Prototypes for overmoulded parts or those with integral gasket material—a soft touch handle, for example, or a cover containing a rubber-like sealing surface—should either be designed with zero clearance or up to 0.05mm interference fit. Leave any sort of gap and the components might come apart in your hands, leading to a redesign, reprint, and loss of time in the development cycle.
Advantages: What Can PolyJet Do for You?Protolabs uses Objet500 Connex3 PolyJet machines that can produce parts with a range of hardness levels, from rigid parts to flexible elastomeric ones with a Shore A hardness value of 30A (similar to the gel inserts in your shoes). Agilus materials are used for added tear resistance and tensile strength; black, white, and clear colour options are standard.
As with overmoulded part designs, be sure to upload each piece of a “multi-part” assembly with its own separate CAD file, together with one that contains the entire assembly. Select the material hardness, colour, and quantity and you’ll receive an instant quote. Once ordered, parts typically ship in 1 to 3 days.
In summary, if you’re designing a part that will be overmoulded, PolyJet is for you. Prototyping a two-shot, injection-moulded part? Take a look at PolyJet. Need a part that’s rigid in one area but flexible in others, or translucent in some places and opaque in others, then PolyJet might be right for your product. Working on an LSR prototype? Yep, PolyJet again.
As always, feel free to contact one of our applications engineers with any questions, +44 (0) 1952 683047 or [email protected].