Re: 3d printers and robots
 

A couple of additional tips - Understand how the part is going to be loaded. Generally, the material will be weaker in one direction than another. Also, use the software to your advantage. The automatic print setting features are great for parts that aren't going to see much loading, but if you have the ability to examine each layer and tweak the print settings, definitely do so. You can minimize the number of voids caused by the printer head changing direction around curves (see here for an example), which can help you in situations where you will have loading, such as around fastener holes.

Re: 3d printers and robots
 

1675 did some experimenting with 3D printing last fall and I'm sure we'll continue that this year. We were mostly experimenting with gears. Most of our tests help up just fine - it was when we hastily reduced material near the hub that we had a failure.

On our 2013 competition bot, we used 3D printed plates for custom gearboxes for our drive train. Our milling and pocketing capabilities are limiting so the ability to print two plates in 3 hours greatly increased our production. We had 8 printed plates and assembled gearboxes by the end of week 1 (normally we're looking at week 3 for assembly). Never had a problem with the plates through 5 competitions so far.

We also printed a guidewheel for our climbing mechanism, but the printer ended up having a breakdown after 7 hours of printing so the actual part on the robot is a lathed piece of acetyl donated by a local machine shop.

Previous to that (2006), one of our mentors printed a fully functional set of mecanum wheels for a Vex robot.

Our school has a Dimension 1200 BST and Stratasys donated some material to the team this year.

Stratasys also donated some polycarbonate printed gears for us that we briefly used to increase the speed of our robot (but ultimately removed in favor of more torque).

3D Printers in Robotics
 

Hi all!
I'm taking a Project Lead the Way course of Engineering Design, and our class is trying to get a 3D Printer to help with our rapid prototyping for the class. Part of this proposal is trying to find other ways it can be used around the school, and I, being an avid FIRSTer, mentioned that I had read about applications for 3D printing on robots from the all-important Chief Delphi.

So I was assigned to ask you all about them.
I know I've read threads about the applications of 3D printers, and that those threads already exist, but I want to know about the printers themselves.

How did you get one (Is it your sponsors', your school's, your team's, etc.)?
What model is it?
What can it do? (Features- multicolor printing, what materials does it print in?)
What features do you find essential for making parts for robots?
What other uses do you find for the machines?

If you want to include bits about some special ways you use 3D printed parts, that'd be cool, but I've read a lot about them already.
Thanks!

Re: 3d printers and robots
 

Apparently my thread was merged with this one, although the threads are meant to be about slightly different things. But no matter.
I'm still interested to get answers.

Re: 3d printers and robots
 

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.

Hopefully, this is some place to get started. There are so many printers out there you can easily find one. I would recommend against going for the cheapest ones out there and also against a large commercial printer (Stratasys) for a school setting. You may be able to get one with support and donated materials, so if it works out in your favor, there is no reason to immediately eliminate this. In the end, it needs to work or be repaired quickly. If you can get a sponsored service contract, this is something that might be worth looking into. However, expect to pay several thousand dollars for a repair call if there is no service contract. (And at that cost, you might as well just buy another Makerbot/Ultimaker/etc.)

You want one that will work, but also one that is maintainable, affordable, and cost-effective. I would not get an SLA printer due to the material costing $200+/liter. 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!

Re: 3d printers and robots
 

Our school's CTE department was awarded a grant to purchase a printer that one classes is now assembling. The second part of their grant is they will use it to print parts for making another printer that will be given to a middle school CTE program.

I will talk to the instructor and find out what make and model the printer is.

Re: 3d printers and robots
 

It's probably some form of RepRap. Wouldn't be surprised if it's a Mendel or a Prusa.

330 runs a modified Mendel. It can't do multi-material; that involves a 2-extruder head (though those are available). Prints PLA, can do ABS but haven't tried that. The one 330 runs has a heated bed and a heavily modified Y-axis from the standard Mendel. (Instead of being largely PLA/wood, it's mostly metal.)

Haven't found too many other uses for the machine yet, but printing random small stuff isn't too hard.

Re: 3d printers and robots
 

So we started playing with 3D printing last year after I built a Linear Prusa REPRAP. Didn't get a lot done for the robot but we did build some slides and electronics mounts. We also printed a ton of wrenches to hand out at competitions.

I taught a 3d Printer class (where everyone built their own printer) over the summer which was attended by both members of our team and some other teams.

We now know a lot more and know what we can print if we design it so I hope to see it used more this year with not just FRC but also potentially FTC.

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.

Personally, of the REPRAP designs I currently like the Prusa I3 although there is a certain minimalist elegance to the Linear Prusa V2 which is made up primarily of Rods and printed parts. I have sponsored a Kickstarter which should deliver me a good Rostock (delta style) printer later this year.
A very reliable vendor of Kits who makes really quality stuff is MakerFarm
(http://www.makerfarm.com) and he offers both V2 and V3 Prusas kits at
really good prices.

There are lots of different host, slicing and firmware options out there. Look up the online version of MAKE magazine which recently reviewed a number of slicing programs. There are also several electronics options but not all firmwares will work with all electronics.

Currently my favorites are:
Electronics: RAMPS 1.4
Slicer: Slic3R
Firmware: Marlin
Host Program: Repetier

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

Re: 3d printers and robots
 

How about a Modified Mendel Max using OpenBeam?

Here's one:
http://www.thingiverse.com/thing:33946

I have been trying to find some photos of a full-on OpenBeam Mendel (http://www.hive76.org/modified-mende...ing-wednesday), with only the injection molded OpenBeam components used for framing. This would allow you to build up from components without the need for a 3D printer to make the framing components.

Re: 3D Printers in Robotics
 

We recently got most of the DC Public School robotics teams Makerbot Replicator 2s. We started with the 6 PLTW engineering schools as an easy justification, and added in the 4 other schools with robotics. They have been used for a variety of projects, but not yet used on an FRC robot. Some things made have included parts for a quad copter, camera/Arduino enclosures, and cell phone cases. They only have one colour at a time, but we got multiple colours they can switch around the feed. They will be used in the PLTW engineering classes by non FRC students as well as FRC students.

It's really cool to talk about an idea with students, and then have them put something in your hand the next week.

Wetzel

Re: 3d printers and robots
 

Our FTC team used our 3d printer (uPrint SE) to print out a bucket for Ring it Up, due to the fact that it was three days before competition and they had couldn't get the legos to hold the weight of the rings without collapsing. I think it was about a 18 hour part, with the white build material running out halfway through. Our teacher then switched it to red, making it look like a magnet. The team won the design award at competition because of it, at least that's what they say.

As for FRC, we have yet to really use our 3d printer for anything.

During offseason, people have made cases or stands for their electronics using thingaverse.com, as well as someone using it to make parts for a hexapod and a 3d scanned toy lion. My school also says that they 3d printed a part that broke somewhere that would have cost $$$ for about $1 of material.

I personally have used it to:
*Make two lithophanes for my sisters for their birthday (found software online, can't remember where. Came out really well, especially when I remembered that lithophanes work better when held up to the light :] )
*Sculptures that were artwork from my aunt that I traced in Inventor
*A small print to ask a girl to homecoming last year (she said yes and really liked it. Someone else then copied it and also got a yes)
*Pieces for a tic-tac-toe game
*Two roller coasters of my own creation, one found online (see my instructions and pictures I posted to themeparkstudio.com: http://forum.themeparkstudio.com/index.php?topic=108.0) I mess with this a bunch because I want to be an Imagineer, fyi.

*Our school bought two when it opened, one more when a new department opened.
*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

Re: 3D Printers in Robotics
 

I own a Makerbot Replicator 2X. My job also owns the same printer.

It can do ABS or PLA (I've heard tell of it doing Nylon but I haven't tried it and I likely won't) and can do 2 color printing (or mix and match materials if you want)

I've primarily printed brackets, PCB enclosures, and prototype parts for visualization. I've never tried to use it to print structural parts for FRC scale robots.

Other uses? I purchased it to prototype out parts for small scale educational robots. I use it for its intended purpose. Yes, I occasionally print out small trinkets as demos for people but this is a tool for me and I use it as such.


Overall, I've found the 2X to be a useful tool once it is dialed in. Being able to design a part, hit print, and wake up the next day having the part sitting in the printer is convenient and lets me iterate designs quickly.
Small issues I've run into -

Leveling the build platform is really important. It's not a set once and forget it. I tend to level it before every print or two.

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

Living in Florida there is a lot of humidity, this shortens the effective lifetime of a KG of plastic as it wicks moisture out of the air. When these pockets of moisture hit the extruder they boil and it can cause the nozzle to spit plastic rather than smoothly extruding it. While this will rarely ruin a build it can make it look like crap. I recommend NOT opening filament until you have to use it. If you can store it in a low humidity area that might be better. I don't currently have that option, as such I'm more or less giving my spools a 6 month life time. There are things you can do to take the moisture out of them but they don't seem a) safe b) effective to me so I likely won't do it. Rolls that go bad will probably be relegated to "demo" rolls where I don't care about the quality of the parts just making lots of them for kids or giveaways.

I'd also have serious concerns about letting students run these devices without heavy supervision. Mine gets very hot (bed is 110C and the extruders are 200C+) and they stay hot for a while due to being fully enclosed. Burns are a serious concern.


Otherwise, I highly recommend this printer for prototypes. I wouldn't use it for structural members in FRC though.

Re: 3d printers and robots
 

Verdict is that it is a Rapman 3.2

Re: 3D Printers in Robotics
 

We check if the printer gets moved around, or we notice deteriorating build quality.

As far as the Kapton... It's much easier with an extra pair of hands. What we'll do is to stretch it across first, but only tack down one corner with your fingers. Then run across the plate on one edge, using the other hand to keep the stretching (or, the other person's hands). Then you get the fun part: start in the middle of the platform and smooth the tape down going away from the center/already smoothed area towards the edges that haven't been dealt with. Pick up if you need to get rid of a wrinkle or air pocket. Sometimes you may need to poke a hole in an air bubble with the tip of an Exacto knife to let the air out. Line up the next piece and repeat.

If you really need some advice in dealing with Kapton, find your local R/C aircraft club, figure out who their best monokote applier is, and ask him/her for lessons. Then treat the Kapton like monokote and your fingers like the iron used to apply it.

Re: 3D Printers in Robotics
 

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.