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CAD drawing for 3D-printing plaster mold natches, spacers, clips and embeds
Available as a Product on the Downloads page
Plastic natches are cast into plaster molds to provide a durable and good-fitting interlock between pieces. The traditional self-interlocking 3/8" or 9.5 mm (nipple diameter) one has not proven suitable for mold making based on 3D printing. Our solution is a four-part system.
-13.5mm holes in 3D printed case molds are all that is needed to adapt to these.
-3D printing case and block molds necessitates pouring plaster and rubber into shells with planar mating surfaces downward (they must sit flat on the table). The thin flanges on the clips cause minimal issues.
-Casting an embed into a mold enables gluing (or friction fitting) a natch or a spacer inside.
-The use of embeds permits flat mating surfaces, these can be sanded (for better flatness and fit). They also allow replacing natches if they get broken (assuming friction fit).
-A set of four interlocks (4 embeds, 4 clips, 2 spacers, 2 natches) weighs 8.7g.
Our drawing shows the measurements we use. 3D printing is precise enough that the inside dimension of the embed is the same as the outside of the natch shoulder, yet the natch fits. The same good fit happens with the clip and embed and the natch nipple and spacer (although it is necessary to chamfer the bottom corners and bevel the top corners of the spacer for better insert).
Some dimension changes may be needed to fine-tune for printing in your circumstances.
Available as a Product on the Downloads page
Related Pictures
DIY natches, spacers and embeds in a plaster handle mold
This picture has its own page with more detail, click here to see it.
This is our third-generation alternative to the use of traditional mold natches (like the red ones in the photo). Here is what you are seeing:
Right: A 3D-printed case mold for a mug handle. Clips (retainers) have been inserted from the bottom side. An embed has been pushed down over the one in the rear.
Center: The plaster mold created from it. The embed at the rear is ready for inserting a spacer (the nipple of the other half will it into that). A natch has also been inserted into the embed in the front. These fit tight enough in the hole that glue was not needed here.
Left: Spacers have been inserted into both embeds. A standard natch fits into the one in the rear and one of our natches fits into the one in the front.
Soon the CAD drawing for these (natches, spacers, embeds, clips) will be available on digitalfire.com.
CAD drawing of handle block mold (spareless)
Available on the Downloads page
This picture has its own page with more detail, click here to see it.
I have long wanted an easy way to make molds for slipcasting handles that mate perfectly to specifically shaped and sized mugs (or pitchers, teapots, etc). These are the answer. These shells print quickly to only 11 grams of PLA filament. They peel away from the set plaster with a heat gun to give fine detail and a perfect fit. These use 3D-printed pour spouts instead of a mold spare (printed separately) and enable cutting the joint surface cleanly and accurately before the handle is removed from the mold (a version of this is also available with spares). This is the product of a long development process. This drawing is available on the downloads page.
Worried about mixing or tuning your own casting slip recipe? We have lots of help on doing that. As motivation, consider the benefits of mass producing handles and store them in a wet box with the attachment slip.
Standard 3/8 inch mold natch
Available on the Downloads page
This picture has its own page with more detail, click here to see it.
Once you try these you will never go back to making molds without them. Unfortunately, these are not easy to get in North America. Or even online. But you can 3D print them yourself (we use PLA filament). This design interlocks with standard 3/8" natches used in industry. There are more aspects to printing and using these than meets the eye, here are some aspects to know:
-The base can be widened for sticking on the build plate better. If you need to print large numbers it might be advisable to use a glued plate to make sure they stick well.
-The inner edge is chamfered to ensure better insertion of the nipple.
-Print without infill for better strength.
-These are hollow, no support is needed.
-The bottom can be widened to stick better to the build plate.
-The ribs can be moved.
-A 9.8 mm hole is needed in the mold.
Glue-sticking the 3D printer bed for better adhesion
This picture has its own page with more detail, click here to see it.
Many objects are unprintable due to plate adhesion issues. Some objects print successfully when done alone, but doing many of simultaneously can fail when one releases mid-print. In these cases, objects can be guaranteed to stick using a hot bed PVP glue stick like this one from Amazon (even a paper glue stick can be used, it sticks pieces even better but does not apply as evenly).
-When applied to a heated bed using long strokes it goes on evenly and dries hard.
-It can be washed off and replaced after several prints.
-The glued surface sticks pieces very well, this enables reducing the area of contact and lightening objects (giving success even when the slicer issues a "low bed adhesion" print stability warning. For example, these spacers and clips would normally release from an unglued plate.
-Objects having a large contact surface may not be removable without damaging them or the plate. Or, pliers may be needed to pull objects off (flat-bottomed pieces giving the most difficulty).
-The ten clips (right) are quite delicate, having 0.8mm walls and 0.4mm thickness base flanges. When adhesion is too great these can be damaged when removed with pliers, when not enough they release during printing. We adjust for this by increasing flange diameter when adhesion is too low and reducing it when it is too high.
Downloadable 3D model for melt flow tester block mold
Available on the Downloads page
This picture has its own page with more detail, click here to see it.
This is a 3D rendering of our melt fluidity tester. We have promoted this device for many years as an effective way to compare fired glaze properties (e.g. melt fluidity, surface tension, bubble retention, crystal growth, transparency, melting range, etc). Open the 3MF file in your slicer, move all pieces off the print bed and unselect them all. Then, print each part by moving it onto the bed and using place-on-face to orient it right. Print the funnel wide-side down with brim. Insert the natch clips and embeds into the holes, pour in the plaster, let it set and finally remove the PLA with a heat gun. You now have a working mold to make slip cast testers. Glue the natches and spacers into the embeds, strap the mold together, glue in the pour spout with slip and finish by filling the mold with slip. If the mold is dry, 10-15 minutes should be enough to get adequate thickness (don't make them too heavy). With 0.8mm thick walls, this drawing 3D prints quickly and is easy to remove when the plaster has set (using a heat gun). The halves interlock using natches (requiring our embeds and related parts). The mold halves can also be lined up by the outer edges before clamping them together (thus not requiring natches).
Links
| Projects |
Mold Natches
Natches are an interlocking mechanism using in plaster molds for ceramics. They enable quick and accurate registry when assembling multiple pieces of a mold. |
|---|---|
| Glossary |
Casting Slip
Casting slips are among the easiest clay bodies to make yourself. The ability to make and tune your own will open many doors in your production process. |
| Glossary |
Mold Natches
At digitalfire we are big fans of slip casting and want to help people and companies (even hobbyists) to integrate it into their production. |
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