New patterning techniques + advantages

[RockyAussie]

In the long ago past, I did a lot of my patterning by hand down onto card stock normally something along the lines of a manila folder that gave the advantage of having a fold line down the middle when open up. This worked out that often a piece only needed to be drawn and cut on one side then folded to get the other side the same.

Next thing that came along was drawing programs like AutoCAD which I still use today a lot. Along with this an A3 printer gave a huge improvement in the time it took to produce a workable pattern. Being able to go back to a drawing and make subtle changes and corrections without redrawing the whole pattern again was a fantastic improvement.

A few tricks with the card stock like applying a coat of spray glue and letting it tack off before using it to cut out the component pieces works good but only until the card stock gets too many knife nicks/slips into the edges. Then the pattern has to be reprinted and cut out again. In the making of this key case you can see this method being used if you like

Normally in running a production type leather goods business you have to take a best guess as to when be the time to take these patterns to the knife making stage. This can and often is a fairly large investment and initial sales and interest can prompt a premature investment that can sometimes take years to recoup.

In the last few years a few new fangled things have come in handy to help me overcome some of this problem and have in themselves been a very useful production tools to have as well. Both the following have the advantage of being able to work from the same pattern drawings done in the AutoCad program.  

My big/little laser – It has a large poster board size cutting area and is a small 2.5 watt laser diode. It started off as an A3 Elksmaker bought from Bangood for around $300. It worked well enough and I spent another $600 making it larger and safer with fume extraction, better cooling for longer runs etc. Some more on this can be seen here –

Just recently the making up of a jewellery box prototype and a small production run on it has made me rethink on ways that I can now improve on previous methods used in both the pattern cutting and small run testing.

The full cost of the knives to be made for this job in the past would have been around $1000. With the strawboard/stiffener pieces I have been able to nest the pieces together and do multiple cuts with a labour time frame that ends up similar to clicking out on the clicking press thus saving around $400 in knives. The actual cutting is slower than the clicker press but while the laser is cutting I am able to keep working on other things. No wasted time and no need to have hard copy patterns to store and use. Cardboard and knives both chew up a lot of storage room.

For illustration purposes I will now show how in this jewellery box some of these new techniques are employed.

This first pic is just to show the jewellery box

 

This picture shows how the little laser can cut out enough strawboard stiffener pieces to do 5 of the jewellery boxes in one cutting. This is 7 different patterns that would normally be made up into knives in the past.

This next pic shows another stiffer board that gets used in the top lid section and here I am cutting enough for 10 boxes in the one cutting. Another knife saved.

This pic shows my latest idea of using a 3D pla+ printed pattern/template for the cutting out of components. The pla+ is a little like teflon and gives a hard wearing surface that I have found to be VERY good for this application. Here is one part way through the printing process.

This one shows a bit of an array of the patterns about to go into use. At the back is the 3D printed jewellery box parts along with a finish box. The ones with handles on top are for the cutting of pieces.

here I am cutting out some of the leather tops/bottoms for the boxes.

With a little bit of practice I was able to get the cutting time down to around 30 seconds per piece which is not all that much longer than I allow for clicking them out on the clicker press.

Works for cutting the velvet fabric quite well as well

and fabric

There is one more little thing that I found very useful with this type of template/ pattern system but I will have to post more on that tomorrow as dinner is now ready.

 

 

 

 

 

 

 

 

[noobleather]

Great information there!some cool tech and engineering.thanks for sharing.

Inspiring stuff

[Rockoboy]

9 hours ago, noobleather said:

Great information there!some cool tech and engineering.thanks for sharing.

Inspiring stuff

[dikman]

PLA is surprisingly tough. It's when you have file/cut pieces that you realise just how tough. Pretty simple - and cheap - when you need to make replacement pattern pieces.

[RockyAussie]

3 hours ago, dikman said:

PLA is surprisingly tough. It's when you have file/cut pieces that you realise just how tough. Pretty simple - and cheap - when you need to make replacement pattern pieces.

True and and after a few runs with the pressure of the knife on the edge it hardens up more and gets more slippery. I really was surprised how much quicker it made the cutting compared to carefully cutting around the edge of cardboard/cardstock.

[RockyAussie]

The other little advantage I found is that as the cutting pattern pieces are done it is really quite simple to do an offset on the drawing and print jigs and moulds etc to expedite the folding and forming and such. This is one example below which is for the tab on the box. I was able to print both pieces together in this case.

Top leather piece and stiffener glued and ready

Leather into the recess with stiffener located

The guide for cutting the backing leather is used to push down into the cavity

push out the other side

Fold down and clip excess of the corners

Glue on the backing which has been colour edged

10 now ready to be stitched.

To finish off a lot of these pieces could be done on a laser with a bit of gluing and such here and there and on larger pattern pieces over 8" square (my printer bed max size)  I would have to go that way. With my little 2.5watt diode laser I would be limited to 3mm black or red acrylic sheeting . Could always glue 2 bit together if I wanted more strength I suppose.  The cost would likely end up more though.

That's all and I hope that is of some help in some way for you in the future if not now.

 

 

[RockyAussie]

On 11/2/2019 at 8:34 PM, RockyAussie said:

My big/little laser – It has a large poster board size cutting area and is a small 2.5 watt laser diode. It started off as an A3 Elksmaker bought from Bangood for around $300. It worked well enough and I spent another $600 making it larger and safer with fume extraction, better cooling for longer runs etc. Some more on this can be seen here –

The link I intended to put in above when I said this was this one -

Sorry about that........I'm gettin old or would ya believe more stupid

[billybopp]

That's awesome, @RockyAussie.   Yet another reason why I need to get into 3d printing, and maybe even laser cutting! 

This is a great thread on matching production level to the tooling and techniques that you use.  If you make all one-offs, then paper patterns are just fine. You have to lay out and cut pretty carefully (slowly) with those, tho.   I don't do production, although I've made several of some items.  For those, I use thick cardboard with clear plastic glued on both sides to stiffen, pretty similar to what you used to, and have as yet to wear one out - but I also haven't done more than a dozen or so of any one thing.   Using a pattern like that goes faster, since you can ride your knife along the pattern but still have to use some care to not cut into it.  I have a couple of acrylic patterns that I've purchased - very similar to what you've printed and they go very quickly by comparison - love 'em!   I suspect that where it might make sense to go with a clicker & die would be where you want a production run and have a lot of inside cuts or something fairly intricate - as in this recent thread 

 

That's where the expense of clicker and dies might pay for themselves in the time saved punching all those holes, inside cuts and such.

You'll see the same principals involved in building cars and airplanes.  GM or Ford have to build MANY thousand cars to make it worthwhile for them to make the tooling and processes in order to hit a price point.  Porsche and Ferrari use more manual processes because they don't do the same production numbers, and have more leeway in their higher prices.  They just can't price justify the tooling to go fully automated.

Thanks again, Brian!

- Bill

[RockyAussie]

19 hours ago, billybopp said:

That's where the expense of clicker and dies might pay for themselves in the time saved punching all those holes, inside cuts and such

I thought about that with the one that I was doing in that post but the knifing cost with all of those holes and slots would be way up more than I would like to commit to. I thought about doing it on the laser but I didn't like the look of all the burn holes to clean up after. I have been tossing up whether to get the knives done just for the outside cut then print a pattern with enough thickness to hold all the tubes and slits and do it as a second cut. I'm thinking off using some stainless seamless tube and just sharpening the end like I do my hole punches. Whack them in a drill and spin them sharp off the side of my belt sander and polish up. Might be worth seeing how much I can get the hole punches from some dye making supplies first though. I have seen them set into acrylic before and I think they would work better in the pla+ print myself.

Regards Brian

[chrisash]

sorry answered my own question after i posted it

Edited November 4, 2019 by chrisash