Mendel VS Thing-O-Matic

Hello,
I am interested in getting a 3D printer Kit, and I have narrowed my choices down to a RepRap Mendel and a MakerBot Thing-O-Matic. I'm hoping that someone has experience with both of these printers and can give me some advice about the pro's and cons of each. I've read many threads about each, but have not been able to find a thread comparing the two.

Are the final products comparable? (the things that they make)

Is the print resolution similar?

I know that the thing-o-matic has the automated build platform which sounds pretty cool. I also understand that it uses a DC motor, not a stepper to feed the plastic into the nozzle and this can may reduce the accuracy of the printing. I guess my question would be, can you see the difference in the finished product?

I imagine there are several other aspects here that I don't even know to ask about. I'd certainly appreciate feedback from anyone who has experience with both.

Thanks!

I own a Reprap (repstrap to be more technically correct) and built a Makerbot for my employer (he wanted to evaluate if we could benefit from rapid-prototyping before dropping ten grand on a commercial printer). Our makerbot is a pre-TOM version, so I don't have any personal experience with the ABP, but I am familiar with building and operating the rest of their printer and I have read some comments about the ABP from others.

I could go into a detailed explanation of all the pros and cons, but it would take you an entire day to read I'm going to keep this as simple as possible and just recommend that you get a Makerbot. Some users have had problems printing on the ABP that TOM has, but you can always "downgrade" or rebuild it into a more reliable heated build plate if it doesn't work for you.

If you find the small build space too restrictive, you can print reprap parts later. Having mastered the fundamentals on a smaller and less fussy machine, your reprap build will then go much smoother, you won't have to pay $100-200 for printed parts, and you will have a backup printer if something breaks.

The extruder technology is fundamentally the same between the reprap and makerbot projects, so resolution wise, mendel can do anything TOM can and vise-versa. Resolution is affected by your nozzle size and how much time you invest in tuning your printer more than anything else.

Used to be that the makerbot was cheaper, but there was a recent blog post about how that's no longer the case. Self-source prusa mendel is the cheapest, and by far the best value as well. If you don't want to screw around with it (great learning experience, highly recommended) then you buy the UP! printer.

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I'm building it with Baling Wire

Both. I've had my ToM since Xmas and now I'm starting a Mendel build. I'm also working on CNC machine. You can't have too many robots!

Thanks for the input everyone. I appreciate the advice, though I'm still not certain which direction I'll choose.

I have a thing-o-matic and I'm waiting for the parts to arrive so I can start building a Mendel. For one reason or another my TOM has been broken longer than it's been working...but when it worked it worked great! I think the biggest difference is that the TOM comes with a support staff you can pester with questions and RMAs; the Mendel doesn't. Aside from that, aesthetically the Mendel looks like a pile of scrap parts until it starts moving, while the TOM looks more like an appliance (with custom wood paneling

If you want to try 3d printing out at the absolute lowest cost I think a Prusa Mendel will do it. Of course, that's the lowest UP FRONT cost since it will cost you more in time, money and effort to build it and keep it working than if you got a TOM. If you want to go with a general CNC bot that can also do 3d printing the wolfstrap and any number of other projects can get you started for even less than the Prusa, but they do demand a certain amount of preexisting handiness.

The ABP is kind of cool. I haven't used it to print a que yet, but I don't doubt that it could. When I get it working again I'm going to set it to the task of making me a set of parts for a Mendel, which should be a good test.

Sounds to me like your ToM is the pile of scrap. Don't you see the irony in making unsupported claims that a Prusa would be more work to build and keep running when in fact you are having trouble doing exactly that with your ToM?

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makeme
For one reason or another my TOM has been broken longer than it's been working...

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Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

No. I put all the information necessary to evaluate my $0.02 in the post, so there's nothing ironic about it. When you can come up with mean time to failure numbers that compare the Mendel to the TOM you'll have something to add.

Until then all any of us have are anecdotes. I shared mine, and summarized the ones I hadn't personally experienced. What did you contribute?

i'm not trying to pass judgement here but what specifically about the ToM has given you issues? faulty parts? not following the manual? human error? (in which case don't worry most hiccups are human error)

i personally would go with a mendel.. the whole self replication thing, open source=more and faster developments, you can do the whole thing for cheaper, and while the ToM can print indefinitely the mendel can print many more parts at once which means the layers have time to cool down and you get better quality prints. (i think?)

i would prefer to use a stepper on my extruder as steppers have been over engineered to compensate for not having
any feed back so they are more accurate and will last for my lifetime where as a DC motor might eventually die and if you're not there the plastic lining in the motor can catch on fire and sparks can fly out onto flammable things... (well i dunno that has happened to me with larger DC motors at work that get used constantly)

i haven't really read anything to suggest it doesn't work but i don't really like the idea of making machinery out of thin lazercut wooden parts. ABS seems a lot more suitable for making a machine that is going to be as reliable as possible. You would think they use laser cut parts so as to make the printer dirt cheap but you still find they have pretty hefty prices on their kits, huge costs to ship internationally and their electronics just took a huge price jump where as all other electronics are getting cheaper.

also while MB probably have tech people to help out, reprap has the forums where you have quite a thinktank of folks who are usually pretty quick to respond.

Reprap also has the irc channel which I have found quite valuable. There is a wealth of knowledge there available often at a moments notice. That is my second port of call if a google/forum search doesnt yield answers quickly, and I have often found the answers I need there. For the questions that werent immediately gratified, I use the forum. You have to wait a while to get an answer on the forums sometimes, but I havent been let down yet.

Edited 1 time(s). Last edit at 02/04/2011 09:28PM by Greg Frost.

mlagana Wrote:
-------------------------------------------------------
> what
> specifically about the ToM has given you issues?
> faulty parts? not following the manual? human
> error? (in which case don't worry most hiccups are
> human error)

The first thing was faulty parts. The current theory is that some of the Kysan DC motors (not the highest quality thing in the world) have (or develop) a shorted winding. That short spikes the current demanded from the motor driver IC, so it shuts down. Over time it just breaks permanently. As far as I know the Cupcake and TOM are the only designs that used a DC motor extruder, and it was just a problem with the hardware that wasn't frequent enough to show up until they went into increased production. The cool thing about buying from a company with support is that they simply sent me a new extruder controller board. So, there was a while where I was diagnosing that issue and waiting for the new part. The second thing was that I added when I should have subtracted and dragged the extruder nozzle across the heated build platform. That scrapped the plastic off of the top of it and the 12v in the resistor wires shorted back through the thermocouple. I just got a replacement thermocouple IC so hopefully I can get it up and running again soon.

> i personally would go with a mendel.. the whole
> self replication thing, open source=more and
> faster developments,

MBI does all their stuff open-source, too. You can find all the parts lists, schematics, and reasonably complete explanations online. They just make some different decisions because they're designing for large batch sizes that have to turn some sort of profit. The Mendel design is supposed to be created and assembled in one-off individual units, and profit isn't a consideration. Check out any project anywhere and you'll see a difference between custom projects and batch projects.

> you can do the whole thing
> for cheaper, and while the ToM can print
> indefinitely the mendel can print many more parts
> at once which means the layers have time to cool
> down and you get better quality prints. (i
> think?)

Like I pointed out before, the Mendel CAN be initially cheaper because no one is really responsible for whether or not a Mendel kit works. I've seen some people here say that it took them several months to get theirs running close to correctly. That sort of design can't be incorporated into a business. The Mendel isn't so much a product as it is an idea that lots of people are sharing. Maybe it works for you, maybe it doesn't; there's no one to complain to. Kind of like if you make one of those DIY digital TV antennas from some plans you found on the internet. If it doesn't work correctly, well, tough. Spend more time and money on it. On the other hand, if you buy a digital TV antenna from a company, and it doesn't work, you just return or exchange it.

> i would prefer to use a stepper on my extruder as
> steppers have been over engineered to compensate
> for not having
> any feed back so they are more accurate and will
> last for my lifetime

Yeah, I strongly suspect that the DC motor was an over-step in the direction of low-cost that will be corrected soon. The latest firmware on Git hub (I hear) is being written to work with steppers, and MBI has constructed their electronics to work with steppers. I figure as soon as they use up their back-log of DC motors they'll move on to a stepper extruder and never look back.

> i haven't really read anything to suggest it
> doesn't work but i don't really like the idea of
> making machinery out of thin lazercut wooden
> parts. ABS seems a lot more suitable for making a
> machine that is going to be as reliable as
> possible. You would think they use laser cut parts
> so as to make the printer dirt cheap

I suspect it's related to that, but not exactly that. My impression is that they wanted to make their kit easy to assemble and, aesthetically, they wanted it to at least resemble a finished product. They're dead on when they explain that if you can put IKEA furniture together you can get one of their bots together. And, because of the fully boxed nature of the design you can get something equally as rigid as the Mendel without all the heavy fasteners. The strenght comes from the combination of all the sheets working together; the size and strength of the fasteners isn't really important. It's just a series of decisions aimed at selling a product that results in a different set of solution.

> also while MB probably have tech people to help
> out, reprap has the forums where you have quite a
> thinktank of folks who are usually pretty quick to
> respond.

True, but again, they're trying to start a business. You could argue that the greater activity on the RepRap forums is because people HAVE to get help, as compared to the lower activity on the Makerbot forums indicating that people don't need help. I dunno. I've never seen any information from either group about how reliable the two approaches are. I suspect that the RepRap group has simply never collected it, and that the MBI group doesn't think it's important to release.