- The maximum part size is 19.3 in. by 15.4 in. by 7.9 in. (490mm x 390mm x 200mm).
- The minimum feature size for PolyJet parts is 0.012 in. (0.3mm) in any direction. Unsupported walls and part features can be as small as 0.030 in. (0.75mm) across, but those serving in a functional or load-bearing manner should be at least 0.040 in. (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 +/-0.005 in. (0.1mm) for the first inch, increasing by +/-0.001 in. (0.025mm) 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 0.030 in. (0.75mm) across, especially those with a depth-to-width aspect ratio of 2:1 or greater. 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 overmolded 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 0.002 in. (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 Objet350 and Objet260 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 color options are standard, although custom grayscale mixtures are also available.
For overmolded part designs, upload the assembly .stp file. A drawing or material map should be attached to indicate desired colors and durometers for each component. Once ordered, parts typically ship in 1 to 3 days.
In summary, if you’re designing a part that will be overmolded, PolyJet is for you. Prototyping a two-shot, injection-molded 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, at 877-479-3680 or [email protected].