Chief Delphi - 3d printers and robots

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Re: 3D Printers in Robotics

Quote:

Originally Posted by evanperryg (Post 1290978)

I've heard good things about Makerbots, but have never played with one. Try to get a decent-sized one, though--the small ones might not be worth it for robot parts, or they might be.

I would try the following experiment, regardless of what printer you opt for (and I might even go for a RepRap kit build to start with...).

If you have one 3D printer, you can build the plastic parts for a RepRap for cheap (if you're willing to put in the time)--definitely under $100 worth of plastic. It'll also help you with dialing in the machine. Now, with those parts... build another. (You'll need to get the metal, electronics, and possibly the print head--figure about $1K for the lot.) Nothing like building a machine to understand the nuts and bolts of how it works.

Re: 3D Printers in Robotics

Quote:

Originally Posted by evanperryg (Post 1290978)

/snip
Intro to Engineering and Design, or Principles of Engineering? If you are doing Intro, I still have all of my notes from last year if you need some of them for whatever reason. Also, those long definitions, word for word, man. One word off and you lose points.

Engineering Design and Development
http://www.pltw.org/our-programs/hig...eering-program
The last one here. I'm a senior and I've already gotten four PLTW college credit courses done.

Quote:

Originally Posted by stinglikeabee (Post 1290729)

Off the top of my head, here are some printers:

Ultimaker
Makerbot
RepRap (Mendel, Prusa, Kossel, Rostock)
UP! (inventables.com has these)
Buccaneer
Stratasys

Things to look for: reliability, ease of maintenance, replacement of components, material costs.

Multi-color: This is not a requirement for most things. It will make your peices attractive, but at a huge increase in cost. There is a printer out there that can print any color on demand (I already forgot which company made it).

Extruders: There are two basic designs: direct-drive or Bowden. Many Bowden setups require fine-tuning to dial in the retraction rate. Direct-drive is basically a stepper motor on the print head which feeds directly into the hot end.

Hot end: This is the part that melts the plastic filament. Depending on how hot / how well the temperature is maintained, this will limit your material selection.

Heated bed: This is important for ABS plastic. It allows the first layer to adhere to the print surface and helps keep the next layers on target/aligned when printing up since the base layer has set well.

Materials: ABS, PLA, Polycarbonate, Nylon, Wood

Overhang:The overhang is basically how well the printer can print an "arch" without having to put support pillars under the arch.

Slicer/G-code: The software and firmware that convert the 3D model into paths, set the retract speed, print head acceleration and speed, as well as the thickness of the outermost wall (shell). Fine tuning in the printer software will result in huge variances in strength (more plastic is not always better), cost, weight, and durability.

/snip/

If it is for an engineering design class, why not have one that students and teachers can build, take apart, fix, and use. In fact, most of the videos are probably on YouTube already!

That's some awesome information there, Tim. And I'll bring up building one. Is it more cost-effective than buying a COTS one?

Quote:

Originally Posted by Bald & Bearded (Post 1290778)

/snip
That said to add to what folks said above - Calibrate, Calibrate, and Calibrate.

From a cost basis the REPRAP kits are affordable and from what I have seen if carefully assembled and CALIBRATED can print things as good as the lower end commercial models.

Plus if the kids do the assembly and calibration it is an opportunity to learn about a lot of different concepts.

/snip/
I am looking to offer the 3d Printer class in the Northern Virginia area again later in the fall. Contact me directly if interested.

I'll look into the kits. And emphasize calibration. :P
North Virginia might be a little far to go for our class, though :D .

Quote:

Originally Posted by eli2410 (Post 1290931)

/snip
*uPrint SE is the main one we use, a powder one that doesn't have strong material that is used by the bioscience department for printing of dna strands that we have no access to (also not sure if the software on it supports inventor models or anything else we would want to make). The other (another department has it and doesn't like us using their stuff, but if ours is broken or is running something big, they will occasionally let us) is a uPrint SE plus. Our high schools have makerbots
*Support material (big thing for complicated parts that some don't do!)
*I personally think support material is a must, since it can make really complicated parts and models, like roller coasters
*See above

Does the uPrint support importing Inventor models?
Is that a feature that is standard among a lot of 3D printers? Or is it only specific ones?

Thanks for your help, everyone! This could turn out really well for us.

Re: 3D Printers in Robotics

Quote:

Originally Posted by Thunder910 (Post 1290986)

That's some awesome information there, Tim. And I'll bring up building one. Is it more cost-effective than buying a COTS one?

I would say that it's a better value. That's not necessarily the same thing as cost-effective, mind you.

For building one, the pros:
--You know the machine VERY well.
--You can do some mixing and matching of parts.
--Cost tends to be lower for a larger machine. A large one could be in the neighborhood of $2K, depending on exact size and features. A smaller one could end up closer to $1K or possibly even lower--again, dependent on features and exact size.
--Build one, build a dozen over the next 5 or so years. (could be faster...)
--Adaptable to new technology fairly easily.

And the cons:
--You need some basic tool skills going in, both mechanical and electrical.
--Still have to buy the parts.
--May get the fun of incomplete assembly instructions. Trust me, that's not fun.
--Calibration will probably take a lot of time--nothing is done for you.
--May need to spend extra $$ to replace parts.

Re: 3d printers and robots

I'd say get a COTS unit that has an open-source history so you can learn from it. Something like the Ultimaker would fit that bill.

There are mixed reviews on the Makerbot Replicator 2/2X, but that is probably a solid choice. With the recent acquisition (or sell-out, depending on who you ask) of Makerbot by Stratasys, I would expect to see reliability improvements and some commercial flow-down into the more mainstream printers.

In the end, you want it to just work and work most of the time or be repaired in a reasonable time and at an affordable cost. It's awesome to have a printer you can modify, but if that printer works three days out of the year correctly, then it's not much of a tool. That's not to say you can make an outstanding printer from a well-designed kit like the Ultimaker or Kossel Pro / Kossel Mini (expect these early next year).

While on the topic of the Kossel Pro, I have one coming in December (via Kickstarter), and it looks to be shaping up quite well. It has a 250mm diameter x 250mm height build area, heated bed, automatic bed leveling probe (software leveling of the print), linear recirculating ball rails, and a J-Head hot end for $1100. I'll give a full report once I get it up!

Re: 3d printers and robots

Quote:

Originally Posted by stinglikeabee (Post 1291026)

In the end, you want it to just work and work most of the time or be repaired in a reasonable time and at an affordable cost. It's awesome to have a printer you can modify, but if that printer works three days out of the year correctly, then it's not much of a tool.

This is exactly the reason I have both a SoliDoodle and an Up! printer. The SoliDoodle has already seen heavy modification to make it more reliable. The Up! printer just works.

I've built several RepRap style systems entirely myself since before anyone was really into this. Back then it was the opposite side of the spectrum from the professional 3D printers like the Z Corp. I had access to but not $100k-$150k to buy.

A SoliDoodle printer is less than $1,000. I paid $1,600 for the Up! printer.
The SoliDoodle was already malfunctioning when I got it (early model the new ones have evolved).
The Up! printer had made a large pile of objects and was still going strong.

Now both models give me about the same productivity.

This is incendentally why I am one of very few people that own 2 of a particular LPKF PCB circuit mill.
The other was the prop designer for StarGate.
Sometimes things go wrong or you want to alternate to improve production speed.

Re: 3D Printers in Robotics

Quote:

Originally Posted by evanperryg (Post 1290978)

My team has desperately been trying to get our hands on a 3D printer. We have a budget of less than $2500. Would a makerbot replicator 2 be the best option? I have heard about the makerbots for a while now, and they sound like the best option for a not-$5000-beast-3D printer.

Intro to Engineering and Design, or Principles of Engineering? If you are doing Intro, I still have all of my notes from last year if you need some of them for whatever reason. Also, those long definitions, word for word, man. One word off and you lose points.

There are LOTS of high quality kits for under $2500. You could get 4-5 Linear Prusa Kits for that price.
While you can source parts and pieces yourself I like the full kit approach.
It makes it easier.
For example for the glass I teach my non-profit charges $750 per student. Each student gets a printer, spool of filament, glass, etc. and we make a small margin.

Quote:

Kapton Tape is a nightmare to apply. If anyone has any tips on this please let me know.

I don't use Kapton. Lately my choice is plain window glass, binder clipped to the bed, and sprayed with some pump based extra strength hair spay.
If the part has issues with warping I will resort to ABS juice (1 part scrap ABS plastic to 10 parts acetone) but that has safety issues (flame, fumes,etc.)

For the person who mentioned the class would be too far the non-profit will share it's materials and plans with FIRST teams. Depending on expenses I will also consider traveling to teach the class.

Looking at this thread, I could see a "best use of additive manufacturing" award related to design and functionality.

Re: 3d printers and robots

We used our 3d printer for numerous things. Our hopper, the plate that pushed the frisbees into out shooter was printed (and was replaced a lot due it the force of our pneumatics powering it) our mount for our kinect was printed, it slide into it, had rubber on the inside to reduce vibrations, our illuminator of 30 leds that was a cross section of a sphere (15 degree span left and right, ten up and down) was printed and screwing into our mount for the kinect, and lastly our mount for our onboard processor-o-droid x2. a case and platform were printed for a) installing a fan to cool it, and b) easier to put onto our electronics board. We also printed a holder for our hd camera on our robot, then when the match was over, we'd literally just plug in a cord to it, grab the video, delete it from the camera, and then unplug.

*note* all of our printed components were designed in autodesk inventor, transferred via a memory stick, then printed.

Re: 3d printers and robots

Right now there are many cheap 3D printer kit, so you can get a very good printer for $1000 or less. I believe that the OpenBeam Kossel Pro, the Kossel Clear and the Rostock Max are all very good printers in this budget.
Anyway, any advice for PLA vs ABS printing? Which is more reliable to use on our robot?

Re: 3d printers and robots

Quote:

Originally Posted by Dival (Post 1291955)

Anyway, any advice for PLA vs ABS printing? Which is more reliable to use on our robot?

It depends on many factors: shear forces applied to the part, shell thickness, mesh, how the plastic was printed (layer/pass bond strength). If you are using SolidWorks or other similar software for design, you could do a materials load analysis to see what the forces on the part are. From there, you could select an appropriate material, using tables of material properties from the filmament manufacturer, Wikipedia, or comparable products. Be sure to have a safety factor as different manufacturers and printers do not create identical results! As a good practice, I would always design for ease of inspection and replacement of your 3D printed part.

I would also suggest looking at Taulman 618 and 645. There is also polycarbonate (PC) and high impact polystyrene (HIPS), BendLay (bendable plastic), Laywoo-D3 and LayBrick (for art use) filaments available. These are available from various resellers such as Amazon, SeeMeCNC, Rainbot3D, MatterHackers, and others (I'm not sure what is available in Israel).

I'd love some feedback on these materials if anyone has tried them. I'm going to start stocking up within the next few months and would love to have a good selection of filaments prior to the build season.

Re: 3d printers and robots

I got an e-mail from a friend of mine at Stratasys today... There's a free sweepstakes for one of their 3D printers going on right now. I don't really know anything about the specific printer being given away (and only know a little about the company itself), but with a "total prize value" of $13,900, it has to be pretty decent, right?

Naturally, I want my team to win... but if we can't, I'd prefer it to go to another team than some random hobbyist out there!

http://www.deskeng.com/3Dprinter/

Re: 3d printers and robots

Thanks for that!

Also, I figure I'd share this with you all... FREE CAD software DesignSpark Mechanical. I'm going to try this out over the weekend, but it might be a good option for those on a limited budget or do not have access to Autodesk/SolidWorks products for one reason or another.

Re: 3d printers and robots

We're going a little off-topic, but isn't solidworks and inventor (as well as PTC Creo, which we use here) free for all FIRST teams?

Quote:

This is not really helpful...
Can you sharesome of your expiriances with those materials? (as well as any other material that you find worth checking out)

Re: 3d printers and robots

Quote:

Originally Posted by Dival (Post 1292012)

We're going a little off-topic, but isn't solidworks and inventor (as well as PTC Creo, which we use here) free for all FIRST teams?

This is not really helpful...
Can you sharesome of your expiriances with those materials? (as well as any other material that you find worth checking out)

No, it's about as much help as one can be. You do need to take all those factors into consideration. In my experiences the biggest factor to using these as structural parts is what direction you print the part in. Any forces that are pulling layers apart are more likely to make the part fail.

As for PLA vs ABS - I've always printed ABS. My printer supports PLA but I've never bothered with it since, if I recall, it tends to degrade in the sun. (I live in what is known as The Sunshine State)

Re: 3d printers and robots

Quote:

Originally Posted by Andrew Schreiber (Post 1292014)

As for PLA vs ABS - I've always printed ABS. My printer supports PLA but I've never bothered with it since, if I recall, it tends to degrade in the sun. (I live in what is known as The Sunshine State)

I've got some experience with PLA. Haven't done anything with ABS. PLA is to some extend biodegradable, but haven't tested that at all. I've found that the color of PLA tends to have a pretty hefty effect on how it prints and how it'll hold up. Set for one color, print a nice part, change colors and print the same part with the same settings and it might not be the same--depends on how close the colors are. (White tends to crack easily and without warning, for example; most other colors will at least warn you.)

Re: 3d printers and robots

Quote:

Originally Posted by Dival (Post 1292012)

We're going a little off-topic, but isn't solidworks and inventor (as well as PTC Creo, which we use here) free for all FIRST teams?

Yes, but if you want to design and sell something, you can't use either of them in academic license form.

Quote:

Originally Posted by EricH (Post 1292035)

Great bit of information there. What colors tend to print "better"? When you say the other colors warn of cracking, I assume you're referring to the discoloration gradient when the plastic is nearing its yield stress?