3D Printed Mold for Leather Pocket

[sbrownn]

This is a 3D model of a bag that I designed that I want to produce in leather.  I 3D modeled the bag to facilitate creating 3D printed molds, stamps and templates to use to make it.  Now that the bag is accurately modeled in a CAD program I can create the 3D STL files directly from the model.  The first part I created was the pocket.  I designed and printed 3 parts to form, stamp and cut out the pocket:  a two piece mold for making the pocket itself and a combination stamp and template for patterning and cutting out the pocket flap.   I have uploaded a photo of the pocket as completed from the molding, stamping and cutting based on the 3D printed parts.  The third picture shows the pocket and the two piece male/female mold parts that were used to form it.  The final picture is of the pressing/cutting template used to make the pocket flap.  This process can be used for all kinds of pockets and all kinds of flap geometry and flap designs.    

 

[chrisash]

looks good

[MikeRock]

Is there some particular item that fits in an angle bottomed pocket?

Just curious.

[RockyAussie]

Very well done and thanks for sharing.

[kgg]

Nicely done. Simple and reusable that gives nice consistent results. It is pretty amazing how 3d printing is changing things. I would expect in the next 5 years as the metal 3d printers become more reasonable in price 3d printing will really move forward. Problem, design solution, and print it.

kgg

[Tugadude]

I'm guessing the angle is just a design choice.  I like the idea of creating moulds with the 3d printer.  I presume they are durable.  I guess you can attach the smaller piece to a block of wood.

[HaloJones]

I have been thinking about printing moulds for wet forming, a couple of questions if you don’t mind;

filament or resin printer?

what infill % did you use on the base block?

how thick is the top section of the mould?

if filament printed what did you do to stop any print pattern forming on the wet leather?

 

TIA

 

[RockyAussie]

2 hours ago, HaloJones said:

f filament printed what did you do to stop any print pattern forming on the wet leather

You can get very good results without going over the top of the leather if you want and it does not matter on the underside generally.

 If you see how I did a handcuff pouch in this post should make it clearer. https://leatherworker.net/forum/topic/77677-how-to-make-a-press-for-moulding-leather-pouches-and-such/?page=2

For the fill you may use 20 % but keep in mind that you can put in posts hidden inside and the wall thickness you give on the outside inside can give a lot of strength where you may want it. Sometimes a hole once given say a 2mm wall thickness becomes a very strong support pipe if you get what I mean.That can be drawn inside the solid as a hollow tube and the wall thickness takes care of the rest. This is how you can reduce the print time and still have very strong parts. In the handcuff pouch although the holes on the outside could allow bolting together they are actually there in case I wished to clamp the parts together and the holes are really support poles in use.

 

[chrisash]

Brian, you are a crafty old sod, I would never have thought of those support holes for strength

Edited November 18, 2019 by chrisash

[HaloJones]

Thanks Rocky, some food for thought 

[sbrownn]

21 hours ago, MikeRock said:

Is there some particular item that fits in an angle bottomed pocket?

Just curious.

There is a cap on the bottom of the bag whose contour the pocket fits up against.

15 hours ago, Tugadude said:

I'm guessing the angle is just a design choice.  I like the idea of creating moulds with the 3d printer.  I presume they are durable.  I guess you can attach the smaller piece to a block of wood.

Yes, it was a design choice driven by the shape of a cap piece that is on the bottom of the bag.  I didn't attach anything to a block of wood so I'm not sure what you are referring to.

[sbrownn]

12 hours ago, HaloJones said:

I have been thinking about printing moulds for wet forming, a couple of questions if you don’t mind;

filament or resin printer?

what infill % did you use on the base block?

how thick is the top section of the mould?

if filament printed what did you do to stop any print pattern forming on the wet leather?

 

TIA

 

I used a filament printer with PLA.  ABS is actually a better choice as it can be smoothed with acetone but my printer is much less problematic using PLA.

I have gone down as low as 50% but I usually use 100% as it is more durable and I can do the forming without getting the leather very wet.

The top section of the mold is 0.2" thick.  

If you don't get the weather too wet and you leave enough clearance in the mold the pattern won't transfer.  If you use ABS you can smooth the interior of the mold so there is no pattern to transfer.  In some cases the pattern, if it transfers actually looks good.

[sbrownn]

9 hours ago, RockyAussie said:

You can get very good results without going over the top of the leather if you want and it does not matter on the underside generally.

 If you see how I did a handcuff pouch in this post should make it clearer. https://leatherworker.net/forum/topic/77677-how-to-make-a-press-for-moulding-leather-pouches-and-such/?page=2

For the fill you may use 20 % but keep in mind that you can put in posts hidden inside and the wall thickness you give on the outside inside can give a lot of strength where you may want it. Sometimes a hole once given say a 2mm wall thickness becomes a very strong support pipe if you get what I mean.That can be drawn inside the solid as a hollow tube and the wall thickness takes care of the rest. This is how you can reduce the print time and still have very strong parts. In the handcuff pouch although the holes on the outside could allow bolting together they are actually there in case I wished to clamp the parts together and the holes are really support poles in use.

 

I have experimented around with different infills but basically came to the conclusion that filament is cheap as compared to what you get.  Yes, there is a time factor too but I have found the best way to cut down time and still end up with a strong mold is to use a larger nozzle size.  Like the shoemaker's fairies, I let my printer work at night. 

[sbrownn]

I used over 20 molds and patterns to make this bag design.  If anyone is interested in seeing some of the rest of them I would be happy to post the patterns and the pieces in the order I made and used them.

[HaloJones]

Have you a photo of the finished bag?

[chrisash]

Using molds for gussets are a great advantage to get sharp 90 deg  sewing edges

[sbrownn]

29 minutes ago, chrisash said:

Using molds for gussets are a great advantage to get sharp 90 deg  sewing edges

Absolutely and in fact making the mold for the end gusset for the bag was one of the first molds I made.  I wanted an end gusset that was stiff enough to hold the shape of the bag through all sorts of weather and abuse.  This particular bag was primarily designed to carry a tablet.

58 minutes ago, HaloJones said:

Have you a photo of the finished bag?

Yes, I'll post a couple of photos in a minute.

[sbrownn]

[RockyAussie]

Very nice work. I like the handle holding loops in particular. On the pla+ filament I use I have found that in some areas you can get a good smooth surface by using a temperature controlled soldering iron and a bit of rubbing. I look forward to seeing more of your work in future.

[sbrownn]

9 minutes ago, RockyAussie said:

Very nice work. I like the handle holding loops in particular. On the pla+ filament I use I have found that in some areas you can get a good smooth surface by using a temperature controlled soldering iron and a bit of rubbing. I look forward to seeing more of your work in future.

Thanks,

That's good to know about the soldering iron.  I wonder about what a heat gun would do?  I haven't actually found smoothing the molds to be necessary for what I do but I have smoothed ABS molds in the past.  Now I just oversize the top of the female mold so it forms the leather but doesn't press hard enough to leave a pattern.  That means that you have to really pay attention to the thickness of your pocket leather and make sure you are using the thickness the mold was designed for.  If you don't wet the leather it helps in not leaving a pattern.  With these molds and a press you don't have to get the leather wet.  If you are using Bridle, Harness or latigo leather, just put it in a microwave for ten or fifteen seconds to soften the oils and waxes and then form it while it is still hot.  Once the waxes and oils re-harden it helps the leather to hold it's pressed shape.

[Scoutmom103]

I'd be interested in seeing the molds you made and the pattern and the pieces.   The bag looks nice.   

[sbrownn]

On 11/17/2019 at 3:28 PM, kgg said:

Nicely done. Simple and reusable that gives nice consistent results. It is pretty amazing how 3d printing is changing things. I would expect in the next 5 years as the metal 3d printers become more reasonable in price 3d printing will really move forward. Problem, design solution, and print it.

kgg

The 3D printer and press are the most used leather machines I have.  Together both cost about half as much as a new Cobra splitter or sewing machine.  

2 hours ago, Scoutmom103 said:

I'd be interested in seeing the molds you made and the pattern and the pieces.   The bag looks nice.   

Thanks,

I'll post them over the next few weeks.  I'll also make the STL files available to anyone who wants them.

[dikman]

2 hours ago, sbrownn said:

I'll post them over the next few weeks.  I'll also make the STL files available to anyone who wants them.

That is very generous of you, given the time you would have put in developing them. The bag looks very nice.

A heat gun wouldn't be much use as it would tend to heat the whole thing and soften it. As an aside, I recently used PLA to make a shade to fit on my Garmin GPS in the car. The .stl came from thingiverse and it fitted well. My wife took the car out and left it parked in the sun, it wasn't an overly hot day, about 26*C. I went up to the car about 2 hours later  and the shade was soft and sagging!! Bugger!

[Bert51]

Can you use a more heat resistant PLA or Nylon with your printer or would you have to upgrade to a different printer?

Bert.

[chrisash]

Think the problem is UVA rather than just heat, here in the UK are some possible solutions you might consider, guess they are available Down under 

https://www.makershop3d.com/282-filament-outdoor-use