Design Guideline: Concerns for 3D Printing

As a part of the additive manufacturing area, 3D printing expands the capabilities of conventional “subtractive” manufacturing strategies by way of advanced, embedded, one-of-a-kind half and meeting fabrication.  To reap the benefits of these capabilities, the product designer needs to be ready to create elements and components that maximize 3D printing capabilities with out sacrificing the specified look, really feel and efficiency measures of the tip product.  To that finish, designing for 3D printing is the muse from which high quality components and merchandise are made.

So what are the key parts that the designer ought to contemplate when creating elements and components for 3D printing?  From expertise, these parts transcend the precise mannequin design and take note of the supply 3D materials used, the 3D printer’s capabilities, decision of design information and the 3D software program/firmware essential to run the printer.  Understanding these parts will assist the designer forego untold hours of frustration, and as soon as mastered will place the designer within the quick lane of the 3D printing freeway.

Materials

As many 3D printing practitioners know, all 3D printing filament just isn’t created equal.  Positive the 2 commonplace filament sizes are 3.00mm and 1.75mm, however are these diameters actually exact?  The brief reply is a convincing “No”.  Diameters of three.00mm rated 3D filament are often lower than 3.00mm and will vary from 2.85mm to 2.90mm.  Due to this fact, be sure you use calipers to measure the diameter of the 3D filament plastic earlier than use (see Figures 1 and a pair of) and make it possible for the proper filament diameter is entered into MatterControl.

Determine 2

Additionally, bear in mind that 3D filament high quality and consistency varies by producer.  Typically utilizing cheaper filament could trigger issues down the highway that would simply have been averted if high quality plastic had been utilized.  One other attribute is the kind of end that’s produced on the printed half. For instance, some high quality PLA filament could have a shiny end, whereas cheaper PLA filament have a flat to dry wanting floor end.  Decrease high quality finishes interprets immediately into higher ending occasions and prices.  Observe that each one filament offered by MatterHackers has been totally examined for consistency and can work with all RepRap appropriate printers.

Printer Capabilities

Like 3D filament, all 3D printers aren’t created equal.  Printers range in price, construct measurement, heated mattress, most and constant printing temperature, kinds of filament which may be used and the mechanical precision of elements.  Typically occasions, cheaper 3Dprinters are harder to set-up and calibrate which can be a problem for novices.  Additionally, greater high quality elements akin to sizzling ends, extruders, belts, pulleys, screws/ball screws and motors will end in greater high quality prints.  A heated mattress is commonly handled as an afterthought, however no different part has as a lot influence on print high quality and finishes as a heated mattress.  A heated mattress permits for constant ambient temperatures which immediately have an effect on warping, curing, ending and submit processing.

Design File Decision and Measurement

The usual file for 3D printing is an ‘.STL.’  An .STL file is imported right into a printer controller, e.g. MatterControl, sliced and exported as G-code to the printer.  An .STL file is a floor file composed of quite a few polygons that approximate the floor space of a 3D half.  The extra polygons within the .STL file, the extra detailed and exact the tip print.  There are quite a few 3D CAD applications (see Discovering the Proper 3D Modeling Software program For You) that one could make the most of to mannequin, design and ultimately export .STL information. Nonetheless, as with filament and printers, not all 3D CAD software program is identical.  Good 3D CAD software program permits the designer to export Binary (compressed) or ASCII .STL information and in addition permits the designer to set the decision, e.g. coarse, high-quality, for the file (see Determine 3).  The finer the decision, the extra polygons which are required which ends up in higher printed fashions.  One methodology which may be used to find out the standard of the .STL file is to print a cylinder.  If the curved a part of the outside highlights segmented sections, then the decision of the .STL file is suspect, leading to sub-standard components. Lastly, if doable preserve all file sizes under 5MB.  It will make sure that the slicer outcomes are optimized earlier than printing.

Design Software program

As talked about beforehand, not all 3D CAD software program is identical.  The actual challenge with 3D CAD software program just isn’t whether or not you’ll be able to design correct elements and components, however whether or not one is ready to print the ultimate designed elements and components.  Normally, there are two classes of 3D CAD software program:  Mechanical/Engineering Design software program and Sculpting software program (see Discovering the Proper 3D Modeling Software program For You).  Mechanical design software program often exports pristine or “watertight” .STL fashions which are simply printed.  Sculpting software program incorporates extra free-hand surfacing and is due to this fact extra liable to “leaky” .STL fashions.  So how does one know if an .STL file is watertight?  First, in case your .STL file doesn’t slice, then there’s a good probability that it’s a “leaky” mannequin.  Second, most high quality sculpting software program have instruments to check whether or not there are “bare edges” within the mannequin.  One other widespread device that one could use to repair leaky edges is Meshmixer.  Meshmixer is a useful device for fixing fashions, particularly free fashions that have been downloaded from on-line sources.

3D Printer Firmware

Firmware just isn’t as a lot of a problem because it has been previously.  There are numerous kinds of firmware which are RepRap appropriate, and totally different printers choose freely from the appropriate listing.  Simply bear in mind, that it isn’t as essential to interface with a printer’s firmware as previously to set-up and calibrate a printer for 3D printing.  With MatterControl, slicing and set-up is a breeze, particularly with the software program calibration device that dials within the appropriate leveling settings for any printer, even when the construct plate or mattress is warped.  This highly effective device permits for full management of the printer and better of all it’s free to obtain.

Half Design Pointers

There are a number of ‘greatest practices’ that one ought to think about when designing and printing high quality elements and components.  One offers with perimeters.  If a normal infill share of 30%-50% is utilized, it could be higher to extend the rely or measurement of the strong perimeter.  For instance, some supplies, e.g. PLA filament, are vulnerable to leaving gaps or holes within the prime perimeter, particularly if the perimeter rely or measurement is low.  Double the rely or perimeter measurement to mitigate these gaps and holes.  Due to this fact a fringe measurement of 1mm (or 5 layers utilizing a normal decision) needs to be elevated to 2mm (or 10 layers at a layer peak of 200 microns).  Figures 3-5 exhibit the layer peak and perimeter settings in MatterControl.

One other greatest apply offers with wall thickness within the mannequin, particularly if the mannequin has a hole inside.  Watch out to make the partitions thick sufficient for structural integrity whatever the mannequin’s measurement.  That is notably essential if the mannequin part of half is resized usually after preliminary design.

Helps might be your greatest buddy when you have an odd formed part or half.  Simply keep in mind that printing with out helps is often most well-liked, since printing with helps requires extra submit manufacturing.  In an effort to print with out helps, design your part or half in order that helps aren’t vital.  If designing a whole meeting, take into consideration how the meeting could also be segmented to make printable components the place helps aren’t vital.  For extra data on segmentation and printing giant components or assemblies, please reference Printing Exterior the Field: Exceeding the Construct Quantity of Your Printer.

Different design issues to enhance success in 3D printing embrace the usage of elephant toes, chamfers and fillets, overhangs and mannequin orientation.  Elephant toes could also be designed into the 3D strong mannequin to enhance mattress adherence and to mitigate warping (see Determine 6).  These options could later be eliminated by way of submit processing of the print.  If there are overhangs within the mannequin design of the half, use chamfers and fillets to mitigate sagging and stringing.  An excellent rule of thumb is the 45 diploma rule for overhangs, however some printers could carry out simply as nicely with overhangs at steeper angles.  Subsequent, bear in mind to orient your mannequin in such a trend so that each one the part or half options are simply printed.

Lastly, notice that each one your elements and components can be assembled right into a last product.  With this in thoughts, don’t forget to permit tolerances between your elements and components the place they’re joined collectively or assembled.  Please reference MatterHackers Lab: Design 3D Printed Assemblies to grasp the intricacies of part and half tolerances.

There’s one last item to contemplate when designing a part or half.  One ought to know the way that half can be used or how it will likely be post-processed.  Will the half have to be drilled or will that half come below excessive pressure, compression or forces of momentum?  If that’s the case, think about the 3D supply materials and the way a lot the measurements of the half below stress modifications regarding the materials used.  Beefing up joints, particularly these joints at proper angles is all the time inspired.

Conclusion

There’s extra to 3D printing than designing elements and components and replicating these 3D strong fashions into helpful assemblies.  When starting a design, one should take note of the 3D filament to make use of, the 3D printing gear, the mannequin’s last decision and the restrictions of every 3D CAD software program to manufacture high quality components.  By preserving these key parts in thoughts, together with repetition, the 3D printing practitioner and designer will maximize his/her efforts, leading to top quality completed merchandise.