3DPrinting of Pattern Bars (and perhaps Rosettes)?

#1
I see that Makerbot's new Replicator 2 will print objects up to 11" long, 6" wide and 6" high. This is well within the size of the pattern bars for Kenlocs and perhaps for Plant SL's too. The manufacturer claims the resolution is 100 microns and that the result, in PLA filament, is so smooth there is no requirement for sanding or other post production finishing. Leaving aside the learning curve the price is $2199, about the cost of a cheap laptop.

Is anyone out there considering 3d printing to make pattern bars (or rosettes)? Is PLA filament strong enough to act as a durable pattern bar for a hobbiest?

I realize Makerbot is just one of several 3D printer manufacturers but their price is attractive and I'm told they have good customer support.

I'm not technically well versed in3D printing, although I have seen them in operation using home- made machines. The technology is becoming a really big deal in the jewellery trade, which is trying hard to make the techniques accessible to a broader audience. See, for example, http://3dprintshow.com/home

Any comments by those of you who are more knowledgeable would be appreciated.

BTW, if this has already been considered somewhere else in the OTI Forums, please direct me. Thanks.
Ramsay
 
#2
I've been watching 3D printers for a number of years now as a possible tool for jewellery making. There are some interesting DIY and low cost printers on the market, and they are getting significantly better. Based on what I've seen, none of them would produce a product that would be suitable for a pattern bar (I'm talking about the high end ones as well). The issue you'll run into is the steps between layers. Those layers will cause variations in your cuts. Not to mention that the material isn't designed for this kind of use, and will wear quickly.

Honestly, for $2200 you can get a lot of custom pattern bars cut on a wire EDM. Probably more than you'll need (unless of course your name is Littlestone and you have a habit of making cool new custom patterns...)
 
#3
Thanks for your reply Chris. Not sure I follow you on the "steps between the layers". Can you elaborate a bit? They say that their highest resolution for each layer is 0.00039" and, presumably, that refers to the precision in applying each layer. Not sure why they'd be so chuffed about that if the steps between the layers were comparatively unacceptable. As for the wearability, if a pattern bar could be made this way and it wore out after being used a couple of times, I guess a duplicate could be made for a few cents.

Agree on the cost vs wire EDM but I suspect that once a person developed some skill with the machine they would think of lot's of other workshop ways to use it.
Ramsay
 
#4
100 microns is 0.0039". At that resolution the steps are noticeable between layers. And if each layer was perfectly aligned you wouldn't notice the steps, but they will never be perfectly aligned. Even the high end 3D printers, which are growing with 25 micron layers, have layering artifacts. Remember that resolution is relative. For these guys that is a high resolution. But I couldn't print a piece of jewellery at that resolution. I'd spend more time cleaning up the step lines than I did growing it (that's one of the reasons 3D printers haven't replaced CNC mills yet for many jewellers).

And speaking of grow time, something the size of a pattern bar isn't something you'd print off over lunch. It would take hours. I suspect that grow time would be greater than the useful life of the bar.

How much difference does surface finish make? I have a few pattern bars that were milled, and a few that were cut on a wire EDM. You can see the difference in the quality of cut they leave behind. The milled bars have a significantly better finish than these printed bars would have.

If you can find someone with one of these printers who is willing to print out a small section of bar for you, give it a try. But I wouldn't get your hopes up.
 
#5
I have never printed 3D.

So with that in mind it strikes me that printing the bar or rosette with them laying down would stack identical layers on top of each other so you wouldn't have stepping on the critical surfaces - but, see statement number 1. A rubber, even a big one, going over 100µm steps would not be pretty. For the Makerbot, the spec says in so many words that the layer thickness is 100µm and positioning of the head is much better. That's great for repeatability but the layer thickness is the problem if you are printing a critical surface with a changing Z component. As Chris says, the material is not very durable. It seems that those printers can print with ABS as well and that is said to be more durable than PLA - ABS ain't too awfully tough either and acrylic is harder than both of them. If I were to use a bar or rosette made this way I think I'd only use a really big rolling rubber and that really limits the options.

I sure hope they continue to improve the technology to ultimately lay down sintered tool steel!

I'd like to see all those bars that other guy makes.

Cheers,
Rich
 
#6
You both make some excellent points. While it seems to be changing pretty fast and additive printing technology is starting to be used by some major companies - GE for example - if the past is any indication precision will be the last and hardest improvement to make. I can see durability of the product increasing, driven by demand. Time doesn't seem to be a major consideration in what I've read but then a lot of the current use is for prototypes where the time spent in creation is less important than it would be in production. But we could be surprised on the rate at which precision improves; the rabbit is out of his cage and who knows where and how fast he'll run. One of the guys at our local model engineering club is working on his home made 3D printer to try and get it to cut threads. He's not quite there yet but he's a lot further ahead than he was a year ago. The technology bears watching.
Ramsay
 
#8
If you want to keep up with people who use 3d printing professionally, check out http://3dcadjewelry.com/forum/forum.php. Most of us on that forum are using mills because they are still better than printers. But some of them have high end printers they use every day. There are regular discussions about the ins and outs of the technology.

I've come close to buying two different printers in the past year, but the tech isn't there yet.
 
#9
...
I sure hope they continue to improve the technology to ultimately lay down sintered tool steel!
...
It turns out they do that! Unfortunately, the layer thickness is no better than the plastic printers so significant finishing would be required thus obviating most of the benefit we're looking for by just "printing" the thing. Too bad.

Look up Direct Metal Deposition, or
Direct Metal Laser Sintering

Something to keep you busy in the bathroom when you're bored...

Cheers,
Rich
 
#10
Thanks. Quite interesting and encouraging. You really get the sense, particularly when looking at some of these sites that the accuracy of 3D metal printing and EBM additive processes, as well as the complexity of the metal parts that can be produced, is improving very fast. This is especially apparent for industrial applications in medical and aerospace use. There was a reference to 50 micron layers for titanium deposition on one of these sites. None of them claim to have done away entirely with finishing requirements but since that's where a chunk of labour cost remains you can bet it's in the cross hairs.
Ramsay
 
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