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3D Printer Comparison: $200,000 vs. $2500

additivepartdesign.com

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Re: 3D Printer Comparison: $200,000 vs. $2500

#81

Post by mendelk »

jacquesm wrote: post #17
ChuckMcM wrote: post #7

I enjoyed this article, but perhaps not for the reasons the author hoped. This quote, "With some tweaks to my G code and use of a nozzle that is more suited for higher resolution prints I am confident that I could produce a part that would be very close to the quality of the Stratasys produced part." really summed it up. It sums to "I can tweak my setup and get this part to be good enough relative to the expensive ma…

Welcome to the wonderful world of quality control :) Making something is easy, making something with a high repeat accuracy and very low fail percentage is super hard. I learned this the hard way myself with an IO expander for the Atari ST that I designed. I needed it to drive the lathe/mill controller, the ST simply had too little IO capacity so with a bunch of decoders and latches I was able to drive a much larger…

"Amateurs Practice Until They Get It Right; Professionals Practice Until They Can’t Get It Wrong"

Re: 3D Printer Comparison: $200,000 vs. $2500

#82

Post by jacquesm »

mendelk wrote: post #81
jacquesm wrote: post #17

Earlier quoted context omitted.

Welcome to the wonderful world of quality control :) Making something is easy, making something with a high repeat accuracy and very low fail percentage is super hard. I learned this the hard way myself with an IO expander for the Atari ST that I designed. I needed it to drive the lathe/mill controller, the ST simply had too little IO capacity so with a bunch of decoders and latches I was able to drive a much larger…

"Amateurs Practice Until They Get It Right; Professionals Practice Until They Can’t Get It Wrong"

That's a lovely quote. Passing that on to my pianist friend.

Re: 3D Printer Comparison: $200,000 vs. $2500

#83

Post by jacquesm »

blacksmith_tb wrote: post #77
willvarfar wrote: post #36

Earlier quoted context omitted.

I was thinking of smooth curves. Judging from the photos, even the expensive print has a voxelized appearance. I've certainly seen that in the one 3D print I've handled too. So my idea was to print slightly oversize, then mill and polish for perfect curves.

Don't people often just use acetone or another solvent to smooth the surface of chunky prints (outdoors, I hope)? How effective that would be would vary depending on the plastic, but it seems easier than milling (if not especially precise).

Sandpaper? File?

Re: 3D Printer Comparison: $200,000 vs. $2500

#84

Post by avs733 »

jacquesm wrote: post #78
avs733 wrote: post #74

Earlier quoted context omitted.

when I teach innovation classes we talk about the difference in mindset between making 1, making 10, and making 100 of something (and obviously this would scale to 1000+ but that is kind of beyond a lot of students). Until you have experiences with scaling manufacturing you have no clue. I used to do consulting work on this (my background is in manufacturing). Typically I would come into a company at the prototype st…

This is a key component in why hardware start-ups are hard. Proof of concept: dead easy, as long as physics does not make your product impossible. Prototype: a little harder. 0-series: already quite hard (that's roughly what the story above was about). Mass manufacturing: super hard. It's also why manufacturing samples should never be taken as indicative of what a plant will actually put out and you still need to sam…

>Mass manufacturing: super hard.

And requires skill sets that seem really similar but are not actually all that similar. They are linked through engineering design but yeah...they aren't.

Re: 3D Printer Comparison: $200,000 vs. $2500

#85

Post by sbierwagen »

jacquesm wrote: post #17
ChuckMcM wrote: post #7

I enjoyed this article, but perhaps not for the reasons the author hoped. This quote, "With some tweaks to my G code and use of a nozzle that is more suited for higher resolution prints I am confident that I could produce a part that would be very close to the quality of the Stratasys produced part." really summed it up. It sums to "I can tweak my setup and get this part to be good enough relative to the expensive ma…

Welcome to the wonderful world of quality control :) Making something is easy, making something with a high repeat accuracy and very low fail percentage is super hard. I learned this the hard way myself with an IO expander for the Atari ST that I designed. I needed it to drive the lathe/mill controller, the ST simply had too little IO capacity so with a bunch of decoders and latches I was able to drive a much larger…

  A pianist can do what they do repeatably, youtube miracle 
  workers would end up being booed out of actual 
  performances.
http://grantland.com/features/anthony-gatto-juggling-cirque-...

  Partly this was an illusion created by the combination of affordable 
  video equipment and the Internet; young jugglers now kept their 
  cameras running all the time, so if they hit a trick one time out of 
  100, they could upload the proof and make themselves look like gods, 
  even if they’d never be able to execute the trick onstage, like 
  Gatto could.

Re: 3D Printer Comparison: $200,000 vs. $2500

#87

Post by kragen »

I read this whole article hoping to find the part where he tests the tensile strength, impact resistance, stiffness, and dimensional accuracy of the two parts. It never came. Except for the part where he had a delamination ("split"), which I guess means zero strength for that part of the part.

I've been fairly disappointed with the strength of Prusa-Mendel-printed parts I've made. Even if you don't have complete delaminations, it's easy to get poor layer adhesion, which makes the parts fall apart under the least strain. You can fight that by turning up the temperature and filament feed rate, at the cost of dimensional accuracy (which you can compensate for in theory but I haven't done so successfully, being just an amateur) but the higher heat also weakens the PLA. Maybe this weakening is hydrolysis due to water absorption in the filament; I don't have a way to measure that, except printing the same thing a second time after dehydrating the filament, which I haven't done.

I was surprised to find that 100% infill is not always the strongest option, even holding part geometry constant. Lower infill settings produce a more compliant part, and it can consequently withstand higher impact energies.

I don't think you should hold part geometry constant when changing machines or especially entire fabrication technologies. You should play to the strengths of the machine you have. I know that's contrary to the outlook of 3D printing, but it's true. Things like topology optimization can easily generate forms that are impossible to injection-mold, relatively easy to FDM, and much stronger. If you have the option of 25% infill, you can probably get a stronger part by deploying the plastic you saved as ribs outside the main body. And so on.

Re: 3D Printer Comparison: $200,000 vs. $2500

#88

Post by jacquesm »

sbierwagen wrote: post #85
jacquesm wrote: post #17

Earlier quoted context omitted.

Welcome to the wonderful world of quality control :) Making something is easy, making something with a high repeat accuracy and very low fail percentage is super hard. I learned this the hard way myself with an IO expander for the Atari ST that I designed. I needed it to drive the lathe/mill controller, the ST simply had too little IO capacity so with a bunch of decoders and latches I was able to drive a much larger…

A pianist can do what they do repeatably, youtube miracle workers would end up being booed out of actual performances. http://grantland.com/features/anthony-gatto-juggling-cirque-... Partly this was an illusion created by the combination of affordable video equipment and the Internet; young jugglers now kept their cameras running all the time, so if they hit a trick one time out of 100, they could upload the proof an…

Exactly like that.

That's a lovely article by the way.

Re: 3D Printer Comparison: $200,000 vs. $2500

#89

Post by kragen »

MikeAPD wrote: post #72

Hi, I wrote the article. I am really enjoying the comments everyone has contributed. One major detail I left out was the amount of failed parts that came out of the professional machine prior to getting a good one. I was unaware of the reject rate at the time I wrote this. In addition, the production tool ended up having resin added and then sanded to cover up some of the imperfections on the "professional" print.

What was the reject rate? Also, some of us have asked some other questions about tolerances and material properties in other comments on here; could you answer them? I'm sorry about the somewhat intemperate comments of some of the other commenters.

Re: 3D Printer Comparison: $200,000 vs. $2500

#90

Post by kragen »

aleon wrote: post #10

This is an unfair comparison.. Having used a Stratasys Objet of around a similar price point, the amount of detail you can get is incredible -- down to fractions of a millimeter. Sure, for the prints that were pictured in the comparison, either can do relatively well, but the point of higher end printers is for higher resolution prints, different materials, shapes of the print, etc. To ignore all of those use cases a…

Every hobbyist printer can get down to fractions of a millimeter. I think 100μm surface roughness is typical.
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