Recently I ordered a MakerBot Thing-O-Matic. On Thursday I've got mail: "Your order # ...... has been Complete - Packed and Shipped." Deep breath. From experience I expected the parcel to rest at customs over my hypertonic weekend which it did indeed. And FedEx kept the tension high. They announced delivery until Monday 6 PM. at 5:56 I called them to ask if they'd stand to their promise. While the lady at the call center called the delivery station the bell rang. Receipt signed and parcel taken at 5:58 pm. Twelve minutes left for a first look until departure deadline for dinner with my parents. Honestly, I would never miss a delicate meal for any robot. Lots of parts in the parcel... laser cut wooden parts, boxes marked with names of subunits... Fascinating! I was back from dinner early enough to set up my bot_building_workplace. But first I've read the letter in the parcel. There I found this scaring sentence: "This is an advanced kit." Gosh! I am a manufacturing newbie! Very creative, systematic,lots of ideas. But two left hands, software expert with some soldering experience. Anyway: No guts, no glory! I'll do it! Yes, I can!
Oh, you want to know my current status? It's said that two persons can build it during a weekend. So I expected a week for me alone. Seems that I'll be not too far away from this estimate.
And finally a warning: Get married before you get the kit delivered! You'll need someone telling you when to stop for eating or sleeping.
[Update December 05, 2011] It's up and running!
Assembly was finished on Friday, the 25th after some four working days. Expected to find some spare time after that. Bad idea! I stayed busy enough to be unable to complete this report. As a side remark: On makerbot.com you find something like "plug and play" but that's not really true. Okay, if you consider setup and calibration part of the "play" then this statement is correct. Yes, the first test parts have been produced Friday night. But when I tried to print some larger objects the machine didn't know how to do it correctly. They fell apart, they stuck to the raft, they got warped... Oh, and my gen4 interface kit refuses work. I'll take care of that as soon as I'll find some time for that.
Getting Upset... - Ahem, Setting Up
The assembly instructions tell which tools and materials you have to get in addition to the kit. I recommend flux to improve soldered connections to motors and plugs. And a screwdriver for electric clamps. I have no dedicated workplace for building projects. So I populated the empty table in the living room and spread all tools and materials on and around it. For the first steps it's a good idea to have some large area available to flatten the large heap of parts. To sort and find those you'll need for your next action. Actually, this sometimes is a real challenge if you won't explode all bags of the kit before beginning assembly. They are not really sorted by function or by component.
[Update December 05, 2011:] I couldn't find any shrink wrap in the kit. I recommend you'll get some to cover solder joints of the fan and some two pole header joints.
A word about the Assembly Instructions. I'm a fan of assembly instructions by this famous Swedish furniture store. Detailed, understandable, many images. However, if you want to build a complicated furniture you should look at one already built and exposed in a store. Assembly instructions for MakerBot are similar. I haven't seen a completed one in reality, on videos you see them only briefly, not in different perspectives and only with the body covering complicated elements inside. I'll try to give warnings regarding points where I had some severe doubt or even had to dismount because I was wrong.
X Stage: Automatic Build Platform
At 8 AM I started at the first chapter of the assembly manual. Think about it if you wanna build this device! Sure, it's the innermost part but it is probably the most complicated requiring most delicate skills. Don't wonder if plastic parts like the tubes have a different color. Oh, and you can recognize the low socket bolts by their color. They are shiny, not black which is explained in a later chapter. And they are in a different bag. To loosen the QA sticker you can warm it up. I did it on the kitchen stove. Watch your hands! Really, when warming it that touching just doesn't hurt it peels off nicely. When adding the aluminium tape I've laid it on the kapton roll to distribute pressure. Oh, my kit has two aluminum tapes. Why? And when pushing the tubes on the axle move it straight. It's easier than turning it.
It's a good idea to put the laser cut parts together without fixing to see how they will look like when mounted. Many parts have symmetric mounts but are asymmetric. If you build the base backwards the table mechanism won't fit. Also the belt is not centered and won't fit over the pulleys when lead on the wrong side of the platform. Soldering motor and plug was easy. Here I used a flux pen, took care that the temperature of the iron was appropriate, and didn't move the connection until cold. I checked solder joints by measuring resistance of the connection from plug to motor to ensure that it will deliver full voltage at high current. If you do this you have to ensure the zero-calibration of your multimeter. Mine is a little off. Hmm... the assembly manual tells something about heat shrink covering the leads at the plug. I couldn't find any tube. Will fetch a centimeter of my own repository. Oh, and I will add a drop of hot glue on the leads inside of the shrink tube to avoid short cut under pressure.
Unfortunately, I was too brutal pulling the nuts against the acrylic plates. The wood is rather smooth and soft. Nuts and bolts cut into it so that nuts will be held if you loosen the bolts. But if you give force to the acrylic you will hear it crack - and then it's too late. I broke both acrylic plates of the automatic build platform. I am waiting for an answer from MakerBot Industries how to get replacement parts. Actually, I even wonder how (or if) these plates can stand the tension of the conveyor belt.
Oh, almost noon. Almost three hours instead of one hour as stated in the assembly instructions? Uh-oh... No, I've written this later.
The kit has arrived Monday evening. Two days have past and only a single build platform assembled so far? Don't worry! I've already done much more in the meantime. You can't read more because it is so difficult to move from the assembly area to the computer to write about it. I'll keep you updated! Here a short list what I've done so far:
[Update December 05, 2011:] In the meantime I got the idea to print replacements for the broken parts myself. Hmm... How to convert DXF to STL? The proposals I found on the net haven't been really comfortable. Anyway, I'll get that done. If I don't find any suitable solution I'll write my own Bezier interpolator. And I recommend to follow the tip to replace the conveyor belt with paper. On my fixed ABP the plastic got a little wavy after a short time causing fixing problems for rafts and parts. And there are lots of different papers with glossy, shiny, matte, whatever surfaces. This gives some potential to find the most suitable one. Here I have the advantage of a personal connection to a printing shop. (2D ;-) )
Everything from here is an Update of December 05, 2011
Y Stage
After assembling the automatic build platform this was a piece of cake. Mainly putting together laser cut wooden parts and tightening bolts holding them. I mounted the stepper motor before I added the front and back. This gives better access to the bolts holding the motor. Have a close look at the rods. The kit contains six of them. Three pairs of different length! hold them over the partially assembled X stage when adding them. After putting the caps over them feel if they are held tightly enogh that you cannot move them. Otherwise you will get some serious noise when the build platform moves at high speed. If they are a little loose simply fold tiny pieces of paper and put them under the caps. This also holds for the other rods. It turned out that the stepper motor got covered while assembling the X stage so that you cannot adjust belt tension. I hope I configured it good enough to print the X stage idler tensioner as my first part. The MakerBot is running while I am writing this. Looks a little slanted in Y direction. From what I've read so far the tension might be a little too tight causing skipped steps.
Z Stage
...and it's still getting easier! The Z stage basically is a shelf able to glide up and down the rods driven by a stepper motor on top of the device. I looked through all of the packages for the Z motor flange to be mounted on it. Finally I found it on the worm drive of the motor.
Stepstruder MK7
Now a more demanding task again. Muscles and brain are severely involved. Assembling thumb screws reads like a rather simple task. However, I was unable to push them together straight and strong enough with one or two pliers. And I don't have a vice. (Yeah, I know: Shame on me!) I laid the thumb on a flat hard surface, put the screw as far into it as I could, took a hammer, and carefully hammered on them to connect them. If you listen you'll notice a change in sound when they are at the limit.
There are reports that the plunger ranges too far towards the protruder wheel that it doesn't press the filament to the wheel but blocks it. I also had this problem. Unfortunately this is only noticeable after complete assembly and then you'll have to dismount the stepstruder to remove one of the metal washers to fix it.
And look at the images in the assembly manual really carefully!!! Many parts can be mounted in wrong orientation which blocks the assembly of other parts. I cannot tell how often I have partially disassembled and reassembled the stepstruder to finally get it together...
I've put shrink wrap over the solder joints of the fan to prevent short circuits. And I added wire and header plugs to the temperature sensor to allow for dismounting the stepstruder without opening the bottom of the MakerBot which is not really fun with all the wires placed there.
I was unable to solder the diode to heat sink of the safety cutoff board. It doesn't look really large, anyway. I have temporarily clamped a short piece of .1 mm (.004") brass foil from my repository. I will order a small heat sink, somehow mount it under the diode (glue it? With epoxy? Superglue?) and add some thermal compound to it.
Body
This again is an easy job. After exercising with the other parts so far I even managed to mount the acrylig large plate in the right orientation without marking it. Watch that the vertical rods are really fixed. If you can move them a little up and down add some paper under the caps.
Electronic Installation
First mount all your PCBs to the bottom board of the body. Then connect them as described in the assembly manual. Also connect them to the parts distributed over the device like motors, switches, sensors. The main power supply has to mounted to a side wall. The problem here is that the bolts of the power supply package are too short and the M3x16 bolts seem too thin. I am not yet really sure how to solve this. I won't move my MakerBot very much but I am scared of it moving by itself when printing and shaking the power supply from its mounts. Maybe gluing it? Using 3.5 mm bolts?
One remark about precision when setting the potentiometer on the stepper motor drivers. For instance take the suggested 2.311V for PFD of the Z axis. They don't tell in the assembly manual how they've got the value suggestions. The resolution suggests a maximum error of 433 PPM. I've got a cheap 3.5 digit multimeter. However, the range can only be set in steps of 10 which requires me to choose the 20V range giving a resolution of.01V. And I remember that I have read something about a maximum error of 3% for this device. If I assume this percentage of measured value (not of total range) then I'll get something between 2.242V to 2.38V. Anyway. I am confident that this precision is sufficient. The driver ICs also add some error, not to talk about stepper motors, and friction and tolerances of the laser cutter.
Setting Up the Device
The assembly manual mentions proper belt tensioning. This is also some difficult task - at least for me since I have got absolutely no experience in that so far. As already mentioned above one of my belts seems too tight. I was too frightened from too loose belts that cause some deviations when turning direction. I'll loosen the belt in question so far that it feels as tight as the other one causing no problems so far.
Gen 4 Interface
Soldering the parts to the board was easy. Good quality PCB. Watch that the connectors belong on the other side! The board has vias. I tried the "easy" way to prepare the LCD connector wires. Didn't work for me. The hard way is not really hard if you separate the lines with a wire cutter. Worked for me. Creating the 20 pin IDC cable was a problem. I was unable to give it a straight press and damaged a connector. Luckily replacement was easy to get. The connector which came with the kit can be plugged in both directions. I did it the wrong way resulting in blinking of the power LED and the LCD backlight. Actually, I am not yet finished with this device since some solder joints seem not to connect properly.
Upgrades
There is a page on thingiverse.com listing a number of upgrades. Look through it and decide on your own which are sensible. I am already in the process of making the parts to simplify and improve belt tensioning.
The Bottom Line
Yes, indeed: This MakerBot is my first robot. I did not complete any other mechanical device before. "This is an advanced kit." Yes, it looks like that. Expect several days for assembly and a few more for setup and calibration. And then another few days to get it into productive operation. And it is a real fun device!
3D printing
- Actuators / output devices: 4 stepper motors, heater, 16x4 LCD
- Control method: USB, SD card
- CPU: Arduino
- Operating system: N/A
- Power source: Good old pc power source
- Programming language: Java, C, Python
- Sensors / input devices: thermoelement
- Target environment: indoor
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/my-makerbot-arrived-this-is-so-exciting