MakerBot : Caveat Emptor

I'd like to discuss my MakerBot. Before I start, I must declare that many people have had success with MakerBot, so this post should be taken only as the real-life facts from the experience of a quite possibly less than competent MakerBot operator. With that out of the way :

New owners of MakerBots may be surprised by the amount of additional time and money required to get full performance out of their MakerBot. While this kit is certainly easier than attempting a full blown rep-rap, it has surprise drawbacks which have left many customers disappointed.

The first thing odd you might notice is that the kind, linear assembly instructions trail off just around the time you think you might want to turn on your MakerBot. Don't panic, it is around this time that you should desperately start bothering the MakerBot google group, since if you proceed blindly you might destroy your bot. MakerBots as they currently ship have a number of design defects, which will require your time and money to correct before you can fully enjoy the printer.

1 : The Teflon™ (PTFE) component of the part that extrudes plastic is prone to melting "losing its structural properties and deforming to an extent that it no longer can serve its intended function". If you've calibrated your temperature sensor incorrectly, or done something odd in assembling the hot end of the extruder, you will quickly destroy your MakerBot by melting deforming this Teflon component. What you weren't told is that this part can be protected by being wrapped in a bit of copper pipe and or hose clamp, but the kit doesn't ship with these. If you destroy this part, you will want to upgrade to an equivalent compoent made of PEEK from MakerGear that is significantly more reliable. Indeed, many MakerBot owners wonder why MakerGear extruder parts are not shipping standard with the kit, since most owners quickly upgrade. I spent about $60 in upgrade parts before I even really got started. I don't actually need all that, but I got some spare pieces in case something else breaks.

2 : You may experience inexplicable behaviors of the printer. Some of these are problems with the engineering on the electronics. Essentially, the electronics are not as noise resistant as they need to be. By default, you will need to twist all cables and install R18 ( 180 ohm ) on the motherboard extruder controller. This resistor does not come with the kit. Many people have also had to install ferrite beads to filter out noise from the lines. These do not come with the kit.

3 : You may find that printing objects with a footprint larger than an inch is very very hard. Why is this ? when the MakerBot advertises a 4"x4"x6" working volume ? As the hot plastic cools, it deforms, and as it deforms, it pulls away from the printing platform. Only very small footprint objects can be printed with the default MakerBot. In order to use the full volume of MakerBot, you will need to purchase the heated build platform (HBP) for $50.

4 : The heated build platform kit is hard to build and incomplete. It requires surface mount soldering. Furthermore, the current electronics on MakerBot can not handle the 3-4 amp current the heater draws. You will need to purchase and wire in some sort of relay, solid state or otherwise. Relays don't come from the kit, but a board can be purchased from MakerBot for $15.

5 : Calibrating the software is really, really, hard, and some parts just can't be printed for reasons related more to software than hardware. There is no standard MakerBot calibration file for the 3D printer driver software, but people are working on it. It takes a while to understand this monster and I'm still not done calibrating it for my bot.

6 : The extruder filament feed is under-engineered and hard to make reliable in its present incarnation. MakerBot ships with the MK4 extruder design, but you can buy more functional part from MakerBot for $10, which may or may not solve your troubles, I haven't tried it.

7 : The threaded rods that ship with MakerBot are of sufficiently poor quality that you might find yourself spending days trying to get the Z axis mechanism to work properly. I finally figured out that if I rotated the rods so that they were all bent in the same way, the tension on the driving belt would be closer to constant and my MakerBot would actually work. However, there were many, many days of cursing and manual adjustment, before I arrived at this solution. You can buy new rods at some cost that will be of more correct tolerance. You can also print out parts of a kit ( but not the whole kit ) for correcting "wobble" in your Z axis.

so, to recap :

• replacing the PTFE barrel with PEEK : 13USD from MakerGear
• modular heater core and thermistor from MakerGear : 20USD from MakerGear
• upgrading to heated build platform (HBP) : 50USD
• relay patch for HBP kit : 10USD
• 180 ohm resistor for motherboard : 10¢ ... maybe
• extruder gear upgrade : 10USD
• ferrite beads : ? ( did not use )
• ACME Z rod upgrade : ? ( haven't done )

So, thats totaling at least 100USD in upgrades just to get the bot in decent shape ( not including tax and shipping ). Thats not including unexpected repairs, and all the time spent cursing and wondering what you did wrong.

I guess, now that I look at it, $100 isn't that much, but it is evidence that this product is still in the alpha stages of development and cuts several corners, making it failure prone or downright broken. I am confident that with more time spent engineering, and perhaps with a minor $100-$200 increase in the cost of the kit, to increase the quality of the parts, this could actually be workable.

As it stands, many operators have spent hundreds of hours and been plagued with incomprehensible problems, and have never gotten their bots to print a single thing. Other people have had enormous success. I think part of it is down to luck ( how bent are your particular Z axis rods ? ) and pre-existing skill.

So remember, if you buy one of these, it is not a kit for amateur, or even perhaps intermediate hobbyists. If you are a novice at the time you purchase the kit, you will rapidly be required to upgrade your mechanical, electrical, and computer science skill set. It will take some time, and some people still don't have their bots printing. Budget extra time and money. The design cuts corners that can make it hard to work with, and if you buy now you are paying for design refinement that will finally bring the product out of alpha stage. If you do succeed, enjoy printing your calibration cubes. Maybe in a few months you'll work your way up to this.

What I am disappointed about is MakerBot is shipping these kits as if they worked almost right out of the box. They really should be advertising their kits as "parts only, functional MakerBot may require additional parts and design changes". I think that their advertising has been very effective, with many interviews with diverse news outlets. But, I also think that their advertising borders on false or deceptive, and might take some less experienced individuals by surprise.

update : opinions on the MakerBot forum echo these. There is agreement that the kit takes a lot of time and some upgrading may be required, but that this is generally expected for a DIY kit ( I didn't know that ). The argument is that this is still a fair buy for people with lots of time and patience, and that if they start shipping a huge number of kits they might have to put up a notice to adjust expectations closer to reality.

update : After I thoroughly determined that the Z rod defect was beyond my ability to correct, I asked for two new rods from MakerBot. They are shipping the replacement parts at no cost. So, if something really doesn't seem right, and suggestions from the forum aren't helping, and your rational mind determines that the fault is in the part, MakerBot is willing to replace the defect.

update : MakerBot will soon be upgrading their extruder design to Mk5, which should eliminate some of these problems.

So, issues 1,6,7 should be resolved shortly. Issue 2 of electronic noise has been solved on my bot by simply twisting all communications and power wires, and installing the 180 ohm terminating resistor. Issues 3,4 are inherent to the use of ABS : it will warp if not kept warm during the build. I am told that PLA does not suffer from this. Furthermore, issues 3,4 aren't really issues if you're good at soldering and buy all the HBP parts with your kit. Issue 5 isn't going to go away anytime soon since it requires quite a bit of software development. As the kit becomes more standardized and the variance between bots is reduced, a standard calibration may become available.

So I can now update my recommendation for the MakerBot : Research ahead of time, budget a couple hundred extra dollars, budget extra time, be patient, expect to have to improvise hacks, communicate with the forums and if all else fails the MakerBot people themselves. Learn to enjoy the process of building and debugging. If you're technically competent enough, in the end you will probably get a working 3D printer for a very reasonable price, thats easier to assemble and debug than a RepRap.