lost pla casting

[aonemarine]

http://www.robo3dprinter.com/

this semms like a nice printer if you dont mind the wait, but there is a bit of the learning curve when it comes to printing items. I keep thinking the way I do when it comes to machining parts, wich is totally wrong for printing. For the cost of printed parts, ill just have printedsolid print mine for me for now...

 

[jwcnc1911]

Wow! That Robo is really affordable. I may have to buy that instead of a new laptop and just keep using this one as a desktop for a while.

I'm considering sending him a turner's cube or something to get a quote and to see the quality. All of my 3d printing experience is with big bad-a industrial machines. I've never seen anything that was done on a DIY or home market machine. The pictures you put up look nice enough to get me really interested in it. Do you know the resolution of his machine? That Robo has a layer height of 0.1mm or about 0.004in and can't find the filament diameter. Obviously it's like a dotmatrix printer... the higher the resolution the better the part. However, after all the pictures I've looked at a little gentle filing and sanding could result in a superb part. The little squirrel at the bottom of this page doesn't look so sharp: http://www.robo3dprinter.com/pages/robo-3d-gallery

Here he is:

Make sure your friend hits www.grabcad.com for more free solids than he can shake a stick at. Plenty to print out if he needs ideas. I even have solids of some engines on there under the same username.

Also, if you think that's awesome... check it:

http://www.shapeways.com/materials/steel

http://www.popsci.com/diy/article/2009-08/3-d-printing-now-stainless-steel

 

[aonemarine]

Im familiar with all those websites. Im pretty sure he prints at 1 micron resolution for the fine detal stuff. There is a finishing operation useing acetone vapor polishing that makes the abs printed parts smooth and glossy but it does not work for the pla printed parts.
Here is one of his prints in pla at the 1 micron layer height, I think it is any ways...
Care to guess at the bots name??

 

[aonemarine]

Oh, JW you have to check out thingiverse.com for free stl files of things you can print....

 

[dreeves]

Dave got me into casting and I must say it does not take to long to get started. Dave let me borrow a small tin can furnace and a pattern and I did a brass and aluminum cast in about 2 hours. Most of the time was the little furnace getting up to temp to melt the brass. With the new and larger one should be much quicker. If you are interested jump in. I got lucky meeting Dave with his willingness to help and guide. Thanks Dave

Dave

 

[jwcnc1911]

0.001mm resolution? Maybe 0.001in? One micron resolution is... wicked. What's the diameter of the filament deposition?

 

[aonemarine]

Sorry, its 100 Micron or .0037". Something like that LOL. The filiment varies in his machines one runs a 3 mm dia and the other is 1.75. I think the nozzle diameters are the same at .4 mm
I have probably botched everything I just said so you should contact him to verify. He's the printer and loves printing things up, me I like burning up his prints with molten metal LOL

 

[cfellows]

Although the price of 3D printers has been falling, the quality of prints on the lower cost machines are still in question. I've been collecting parts to build my own to ensure I wind up with a good quality machine and will still keep the cost to something under $600. The secret to good quality prints is positioning repeatability which usually means zero backlash. It also requires long lasting parts to keep backlash at a minimum.

I'm planning to build a delta style printer, like one of these:

https://www.youtube.com/watch?v=3EfxZTI-3B0

It requires fewer parts, the build platform is glass and is fixed position. With magnetic ball joints on the arm ends, backlash can be reduced to nearly zero. There are quite a few variations on this design and there are many parts files on thingiverse.com that can be downloaded and printed.

Chuck

 

[aonemarine]

Chuck, I hope you post a build when you do. Im collecting parts to build one myself and hope to start on it in the next couple of weeks. Ive checked out my friends Robo3d and it is build to a minimum of what a 3d printer can be. it has some z axis wobble issues, the bed cant be adjusted for height, but the thing still does a nice job on printing. I keep thinking these things need to be very accurate and ridgid, but truth be told, they dont seem greatly effected by thier short comings.....

 

[cfellows]

I've been working on a MakerBot Replicator at the TechShop. They are remarkably simple in their construction. Most of the structural parts are made from laser cut plywood and the plastic parts are 3D printed. I have access to both a 3D printer and a high quality laser cutter so printers like the MakerBot and the UltiMaker keep drawing my attention. I could build one for just the cost of materials, there is no charge for using the machines.

The print quality is also based on layer thickness and extruder temperature. I've only used ABS so far and it is kind of finicky about platform temperature as well. I'm going to switch to PLA because it's more rigid and pretty darned strong. However, it will snap when stressed whereas ABS will bend or compress a bit before breaking.

I'm pretty excited about this project. It's very gratifying to draw up an object in Alibre or even Sketchup, write it out to an STL file on an SD memory card, transfer the file to the 3D printer and sit back and watch it get built.

Chuck

 

[RonGinger]

I just got a 3d printer to work. I bought the kit for the Printrbot Simple. As the name says it is a very simple machine. I think the design is rather elegant. It is only $299 for everythinng, electronics, power supply, motors, etc.

I assembeled it with my 15 yr old, nerd, grandson. He did the major work, with me checking over it and guiding him a bit. It took most of an afternoon.

The amazing thing is the first part we tried came out very good. We used PLA, and just blue masking tape on the bed. It took quite a force to get it off the bed.

I had earlier built a SeeMeCNC H1-1. That thing is a hackers nightmare. Its made of threaded rod and plastic connectors. Its big and bulky and rather shakey. I had it running when my grandson arrived, and we tried several prints and never got a recognizable part. I cant decide whether to just tear it apart and put the hardware in my bolt and nut stock, or offer it for sale.

I agree that the current state of these printers makes them nothing but a toy. My hope would be to make a master part for investment casting, but these things look like they are made of the old lincon logs sets. The surfaces are completely ribbed.

An amusing toy, Ill probably drag it along to some of the model engineering shows just to demo.

 

[aonemarine]

Ron, have to disagree......the prints I have been seeing are far better than you describe. Sounds like you have been looking at print jobs with a 300 Micron layer height and a .5 mm nozzle. Most printers will do 100 now and some as low as 50 Micron thru a .25 mm nozzle. No lincon logs there.

 

[cfellows]

One of the things that excites me about the 3D printer is the relatively short process of going from design to finished part. The other advantages are that they are relatively small and quiet, and don't require anything but hand tools to assemble a finished piece. I expect the day will eventually come when I have to give up my shop, but I don't think I will ever lose my desire to make things. The 3D printer seems like a perfect means of satisfying my creative needs in the confines of a small condo or apartment. Not giving up the shop anytime soon, just trying to think ahead a little bit.

Chuck

 

[aonemarine]

Totally agree with you Chuck, and to just add a bit more, the speed for making a rapid prototype and having a working model in your hands is wonderful on these things. Im getting really hooked on 3d printing. combine the plastic print with investment casting....well im sure you can see where im going with this.....

 

[cfellows]

So, what are the steps, once you finished 3D printing the prototype?

Chuck

 

[aonemarine]

Print part, sprue up with wax, mix and pour investment, burn out, melt metal, and pour.
I have another thread on here "lost pla casting 2" that shows the entire process in the video in good detail.
Also my printer has a new filament that's some sort of a pla blend that prints ultra smooth the he claims will be a real game changed for investmentcasting. Can't wait to see!

 

[cfellows]

Thanks for the link to the video. When you burn out the plastic pattern, do you turn the mold upside down so the melted plastic runs out?

Chuck

 

[aonemarine]

Thanks for the link to the video. When you burn out the plastic pattern, do you turn the mold upside down so the melted plastic runs out?

Chuck

Yes it is turned upside down. I used to do this to reclaim the wax, but with the pla I think its just force of habit because it does not seem to run out.

 

[vnkiwi]

PLA burns out, (vapourizes) and leaves no residue

 

[RonGinger]

Yes, the printer I have is about the lowest end of the market- a Printrbot Simple for $299. I think it does have a .45 head.

What printer was used to do the two elephants shown above? I know there are commercial printers with much better resolution.