Saturday, October 30, 2010

Making the extruder work

Today I spend most of my time making my extruder work. I must have assembled and disassembled it about 100 times. But its working now. I changed the place of the thermistor a few times, but that didn't help. I think it is just reading too low values. At room temperature it reads 13°C, which is also too low. So now I just set the temperature to 265°C and the ABS comes out. It isn't bubbling or brown, so I assume its just an incorrect value that is being read. I don't have any accurate thermometers that go that high, so I can't see if my assumption is correct.

I tried printing a few lines without a heated bed, but of course that didn't work. I got some extra nichrome wire to add under the bed and I can isolate it with kapton tape. I hope that will work and I don't get myself electrocuted. As my PSU is really old, I think it will just blow up when I attach the heated bed to it. So I was thinking about using a single long nichrome wire with a resistance of about 160 ohm. That way I'll have 330W of power. My nichrome wire has a resistance of 19 ohm per meter, so I'll need 8.5m of it. That will also make sure everything is heated evenly.
I also have an old thermostat from an oven. That will be more reliable than the one I tried to make myself.

The only thing I'm not sure about is whether kapton can isolate the nichrome wire enough if 230V is going through it and it is being heated. But as it is being used in airplanes, it won't be that bad.

Sunday, October 24, 2010

First Tests

Yesterday I continued building my Mendel. I started by filing the small holes in my extruder to make the bolts fit in there. It took me a while, but everything fits now. I also added the motors and opto's to the printer. When that was done, I attached everything to the electronics board.

After downloading and installing the software, I plugged the usb-cable in my pc and all the motors worked. I had  to tighten the bolts on the z-xis a little more, because one of the two sides skipped some steps. But apart from that there were no problems.

Now that the mechanics were working, I planned to build the hot-end of the extruder. I wound some nichrome wire around the metal part, attached the temperature sensor and got stuck. I found what wire had to be attached to what pin on the wiki, but I couldn't find what pin is on what side. So I went to the webchat and asked my question. Luckily someone was able to help me and told me that pin1 is the furthest one from the power connector. I added that information on the wiki for people after me with the same problem.

Now that the hot-end was finished, I wanted to test it before gluing it to the extruder. I tried many different temperatures from 240°C up to 260°C to melt my ABS and tried to push it through the small hole. At around 250° the plastic started melting, but I wasn't able to push it through the hole. That's why I went even higher with the temperature, hoping it would start coming through the hole. But it didn't help. I just can't push it through by hand. As long as this doesn't work, I'm kind of stuck. I know the extruder can push harder than I can, but it could also break everything. So I don't want to try that. Any hints on this would be appreciated.

I also noticed that mendel-parts sold some faulty green belts. My belts are green, so I mailed to Camiel to know if mine were part of that bad series. I haven't had any problems with mine yet, but as they are part of the bad series, he told me he would send some replacements for free. Really good service from him. :)

Ow and below is a picture of everything wired up. I haven't done all of the cable management yet, so there is a big mess of wires at the top. Prettifying the machine is for when it starts printing.

Sunday, October 17, 2010

Almost done with the mechanics

Today I've continued working on the mechanics. Everything is ready now. I only have to make everything level and tighten the bolts. As you can see, the extruder isn't attached, due to the problem I mentioned yesterday.

Just like yesterday, I encountered some minor problems. During the assembly of the x-axis, I noticed that there were no m3x10 screws for attaching the motor. So I used m3x20 with a lot of washers instead. It doesn't look as good, but it holds everything in place.

I also had to cut the bars holding the x-axis. They were made for the "default" Mendel and not the adjusted part I am using. So I had to adjust them from 495mm to the 463mm that I needed. Now I have 2 bars with ugly endings compared to the ones that were cut in the shop and have a nice and smooth edge. I also burned my finger during the process. I wanted to take the first bar after I cut it, but it was still too hot. Stupid me.

The bearings in the z-axis were really hard to get in place. There was not enough room for my wrench, so I had to use some small pliers instead. I think one of the bearings is slightly sideways because the left axis only turns if the lead-screw is slightly tilted to the right. I hope that won't be a big problem.

That's about everything I did today. I hope I can fix the extruder next weekend and attach the electronics and belts so I can start calibrating everything.

Saturday, October 16, 2010

Starting to build

I started building the mechanical part of my Mendel this morning. I've encountered some small problems, but apart from those it went rather smooth. I started with the extruder. I couldn't find much documentation about it, so if I encountered problems I could ask for help while building the other parts. All the other parts have a nice 3D assembly that I can look at from every angle, but the extruder just has a few pictures.

Once I started building it, I noticed that the bolts didn't fit in the holes in the Idler-holder. I don't know why this is. Maybe Nophead printed the part with too small holes, or maybe Mendel-parts is using bigger bolts than the default ones, or it could also be a combination of both. The result stays the same, it doesn't fit. I don't really know how to make them bigger, as all my files are too big for that and my drill would make them round instead of hexagonal. Maybe I just have to buy a smaller file to do the job.
I also noticed an other problem. Because Mendel-parts assumes I use the older version of the driven-holder and I have the new version with the extra strengthening beam, the screw is too short. I'll have to buy a longer one for that. I should have checked it before ordering my parts.

After those small problems with the extruder, everything went rather smooth. I started building the x-axis. The wiki suggested to use m4x16 bolts for the x-idler-bracked. Those were too short, so I used m4x25 instead and added a second big washer so the belt is between two washers, which should be better for holding it in place. I didn't add the bars yet, as I'll do those at the end.

Once the x-axis was done, I started with the y-axis. The only problem I encountered here was that one of the bearings doesn't turn, even when the bolts are loose. I suppose its broken, so I put it aside. I think there are some extra bearings in the package, so hopefully I won't have to use the broken one. Again I didn't add the bars and went on to the z-axis. That one was easy, so I had a little time left to assemble the frame sides.

Below is a picture of my messy desk after a whole day of building. I hope the building will be done by tomorrow evening, so I can start adding the motors and electronics next weekend.

The last parts finally arrive

So on Monday the 11th my order from finally got shipped. It arrived on Wednesday, but as I only have time during the weekends I'm only posting about it now. The box was a little too small and the steel bars were sticking out of it. Luckily they were wrapped in bubble plastic. I hope they haven't been bend during transport. You can see the weird packaging on the image on the right.

Inside the components were packed in separate bags to make it easyer to find them. The only thing they could have done better is binding something around the kapton film, because it has some small dents and holes from other items pressing against it. (I removed it in the picture so you can see everything inside the box and not just the film) Everything else doesn't seem to have been damaged during transport on the first sight.

To have a better view on everything inside the box, I laid them out on my desk. The steel plates had a funny note on them that they could be sharp. It's like those sunshields for in the cars that say "remove before driving". Kinda obvious those things.

As you can see, the Gen 6 electronics are also in the box. There was even a certificate with them saying it was #14 ever made. They are really a lot smaller than the other types of electronics. I hope that doesn't mean that they can overheat faster. But I still have lots of unused ram-heatsinks if that would be the case. I made a closeup picture of them for you, so you can see how they look. I haven't taken the out of the plastic yet, as it could only damage them. I have enough experience with computer electronics to know that. 

Now that everything has finally arrived, I can start building mu Mendel. I know that I will get stuck at some point, but I hope someone will be there to help me. And now I'm going to start building. Wish me luck.

Saturday, October 2, 2010

Making my thermostat

A few days ago, the shipment from futurlec with my electronic components finally arrived. It took them almost a full month to get shipped and arrive here. Inside the envelope there were a lot of separate plastic bags, all labeled with what was inside. That's convenient.

After a closer look on the multimeter, I saw a big crack in the plastic and the screen was completely loose inside the case. So obviously it didn't display anything. I've sent them an email about this, but they haven't replied yet. I hope I'll get my money back or get a new one. While waiting for their answer, I borrowed one from my grandpa so I could build my thermostat.

I've worked on this all morning, so I was hoping it would work. But it didn't. The voltage to set the desired temperature only goes up to 60mv. So the thermostat can only regulate temperatures up to 6°C. On the positive side: the led goes on for about 2 seconds before turning off, so I think the hysteresis is working, but it never gets cold enough again to make it go back on once it goes off.

I started measuring if all the resistors were correct and found that the potentiometer is 5k instead of the 2k I ordered. All the other ones were correct. I bought the 2k one because futurlec didn't sell 2.2k. I had already send them an email about the broken multimeter and didn't want to send an other one for something worth less than 1€ so I just ordered a 2.2k potentiometer from ebay. I hope everything will work with the correct potentiometer installed. Below I've added a picture of my thermostat. The broken corner is my fault, I dropped the board while I was unpacking it. Luckily its only a small corner that went away, and the rest is intact.

And while I'm talking about electronics, I might as well mention that I'm still waiting for everything from mendel-parts to be shipped. The electronics have arrived in their shop, but my order hasn't been shipped yet. I suppose sending 50 order in one day is a little too much for them. I couldn't do that either.I hope everything will arrive before next weekend, so I can finally start building my Mendel.

Tuesday, September 21, 2010

Mendel 3D renders

Yesterday I was looking on the wiki for some renders of a completely assembled Mendel. The only thing I found was a tiny picture of the front view. That's really too small to be of any use. I did find the 3D-models of an older version of Mendel made in Solid Edge. Luckily my university has a license for Solid Edge, so I downloaded and installed the software. Once installed, I opened the file and wanted to render it.
I got a lot of errors telling me that the included files had an absolute path reference to \\campus\files\MechEng\... well, just a very long path from a filesystem on a university. I looked for a way to fix them all at once. The only solution I found was putting all files in the same folder as the general-assembly.asm file. I was now able to see the whole Mendel in 3D. That will certainly help me once I start building mine.
I made some high resolution renders of the front, back, top and bottom for people without access to Solid Edge. If you click on a picture, you will be taken to a page with the small version of the image. There is a download button on the top left corner of that page. That's the one you need to download the big image. The images are over 1MB each, so you have been warned.
If you want a view from a different angle or from a specific part of the assembly, leave a reaction below and I'll render it for you.

Front view
Rear view
Bottom view
Top view

Wednesday, September 15, 2010

Arrival of the first parts

While I was programming the extension for mediawiki, some parts for my Mendel arrived in the mail. First one to arrive was the nichrome wire for my heated bed. It's just 10m of nichrome wire for my heated bed, so I don't tink a picture is required.

My broken soldering iron
Next package to arrive was a new soldering iron. I bought a very cheap one on ebay. One would think its just a heating element, so even a cheap one is good right? Wrong. After like 5 minutes of usage, I saw sparks coming out of the metal part. I send a message to tk-stores-494 but still haven't got a reply. They really sell junk, never buy anything there. As I wasn't getting a reply and shipping it back to them would probably just be more expensive then buying a new one, I decided to open it to see what was broken. It was all burned inside. That should really not happen after just 5 minutes.
As it was broken beyond repair, I ordered a new and more expensive one from an other store. The new one hasn't arrived yet.

The next day two packages arrived. The smaller package contained the extruder parts I ordered from reifsnyderb with a .5mm and .35mm nozzle. The nozzles are easy to exchange and everything looks sturdy. The bigger package contained the filament I ordered from reprapsource. It was nicely packaged and they even added a small sample of their black filament. I tried inserting the filament in the extruder, and it fitted nicely.

Today the plastic parts from nophead arrived. The box was smaller then I expected, but it was full of plastic. The parts are nicely made and have almost no errors. I hope I can make stuff with the same quality when my Mendel is finally working. To have a better look at them and see if nothing was missing, I laid the parts out on my desk. After comparing them to a requirement-list, it seems I am missing two x-bar-clamp-m3 and two x-motor-bracket-space. It is an old list, so its possible that these parts aren't needed anymore. I'll only know the answer for sure once I start building my Mendel. If anyone knows the answer, feel free to let me know in a reply. It seems its complete, I should learn to watch more carefully before posting.

That's all that has arrived for now. I'll post updates when more stuff arrives or when I did something else worth mentioning.

Tuesday, September 14, 2010

Upload3D extension

During the past days, I have been working on an extension to integrate my stl2png script in mediawiki. I found very little documentation and comments in their source code. It looks like the only documentation they have is how end-users should use it, but nothing for developers. Every function has about two lines of documentation on what it actually does. A little longer description would have been useful. Because of the lack of documentation, it was hard to use their classes and I had to find some workarounds and hacks to make my code work, as an extension is not allowed to change their files. I just made my script change the $_FILES and $_POST arrays. I know that's not smart to do, but its the only way I managed to tell the wiki it should use an other file as source, and not the uploaded zip.

The extension works, but is still in alpha version. The form for uploading the zip still needs work, and the newly uploaded files don't receive a description for some unknown reason. I have temporarily placed a demo of the extension on my pc at home. You can find it on This won't stay there forever and my pc isn't always online, so its very possible that it won't be accessible. Hopefully it will be used on the reprap-wiki by then. The source code can be found on

I'll stop working on this for a while now. With the demo online, it should give people a clear idea of what is possible with mediawiki. Even with the bad documentation, I still managed to make this in a few days. I hope they won't exchange the wiki for an other type of documentation-system. There is a reason that wikipedia is so big, so it would be stupid to change to an other system if you ask me.

Friday, September 10, 2010

A big upload button

As the delivery of the hardware has been delayed, I decided to search for something else that I could do. I found a page on the wiki mentioning that there was a need for a big upload button. After asking, it seemed that they might drop the whole wiki, so maybe the button wouldn't be needed. I don't really understand why they would replace the wiki with something else, as a wiki keeps a history of both documentation and files, so it sounds like a stupid idea to replace it with something else to me.
Anyway, even if they do change the method of keeping the information, it will still require something similar to the upload button. For that reason I decided to make a script in php that would take a zip as input and give stl-files and the matching renders as png-files. I won't create something to integrate everything in mediawiki yet, until I know for sure that they will keep using it.

First of all, I had to re-install a linux os on one of my pcs. I downloaded kubuntu server edition, set up a lamp server in VMWare and added phpmyadmin on the server. The easyest part was already done. Now I had to install povray and stl2pov. I had no problems installing povray, as it was in multiverse of ubuntu (here).
The problems started happening when I had to build stl2pov myself. It seemed I needed gcc, so I installed that one and uncommented the line in the makefile to make it use gcc. The installation instructions now said that everything should work when I used the make command. But it just gave me an ugly error:
Makefile:9: *** missing separator. Stop.
As that line was an include command, I just opened, copied everything in there and pasted that over the include command. So the first error was solved.
There was still a second error however. The program didn't recognize .if !defined(NOPORTDOCS), I thought "this is a new installation, I bet it won't be defined for me" and removed the if-test. The compilation did work now. Once that was done, "sudo make install" installed everything just as expected.

Now that the software was installed, I searched for how to run it. Stl2pov was very straightforward and didn't need any parameters or settings files. It just converted the file. I was happy it didn't cause me more troubles. Povray however did require settings and parameters. The parameters  were well documented on their site and I quickly found that -i is for the input file, -o is for the output file, +W is for the width of the image and +H for the height. I added 2 more options to the command: +GA for giving all errors in the terminal and -D for not showing the picture while rendering. So that makes the whole command for rendering an image:
povray -i\"render.pov\" +W600 +H600 -o\"$output\" +GA -D
Now I needed to find how to add settings to tell the program how to render the objects. After looking a little around the internet, I tried some different settings and these seemed to work. I found a basic script on a site, but didn't save the url. Sorry, if it yours let me know and I'll add a link to give you credit. I changed the colors, rotation, light source and camera location a little, but didn't touch the things I didn't know what they were for like the global settings or sky sphere. It works and that's good enough for me.

The file requires an include-file that describes the object that has to be drawn. It expects the object to be called  MODELNAME. So in my script I had to replace the name stl2pov was giving it. A few simple lines of code later, my php script could rename the model. As the rendering is the most intensive part of the script, I didn't think about efficiency while replacing the name and just wrote something that is quick to code instead of quick to execute. My script was now able to render any given stl-file into a png. I uploaded it to the wiki.

After dinner I still had some free time and quickly added the extra feature of unzipping the contents of a given zip, looking for stl-files and matching png-images and rendering them if they were not found. That was basically just extracting files, looping over them and deleting unnecessary files, so I won't go into detail about that.

You can now find the script I just created in the wiki as stl2png. I added a few lines of comments in there, but really not that much. If anything isn't clear about how it works, feel free to ask me.

Monday, September 6, 2010

Buying the last parts

Yesterday I saw that it was possible to pre-order the generation 6 electronics. I already payed a lot of shipping costs for all the parts I bought, so I hoped it was possible to send them along with the other parts I had already paid for. I send an email to Camiel from to ask if it was possible to change my order and add the new electronics. He was very friendly and suggested to delete my old order and give me a refund. Then I could place a new order with everything together in it.

The combined shipping of the electronics and hardware does mean that the hardware will also arrive later. That delays the building of my Mendel to the beginning of October. But the waiting is worth 7€ to me. In the mean time I can read and learn a little more about it. That certainly won't be bad.

As everything has been ordered now, I can be certain of how much my new 3D-printer costs. In the table below I have put a breakdown of the costs including VAT. All the prices have been converted to euro just like my bank charged me. So there could be a little extra cost for the conversion of the currencies. The total price was a little lower than the maximum of 800€ that I predicted earlier. I also added where I bought the parts, so if you want to buy them at the same shop you can do so.

plastic partsnophead210,33 €22,14 €232,47 €
hardwaremendel-parts.com200,52 €7,95 €208,47 €
electronicsmendel-parts.com177,31 €0 €177,31 €
motorsmendel-parts.com65,45 €0 €65,45 €
kapton tapemendel-parts.com11,9 €0 €11,9 €
thermistormendel-parts.com2,68 €0 €2,68 €
electric cablesmendel-parts.com9,28 €0 €9,28 €
gluemendel-parts.com10,71 €0 €10,71 €
nichrome wireebay3,41 €2,23 €5,64 €
thermostatfuturelec.com7,25 €2,9 €10,14 €
extruderreifsnyderb24,02 €5,12 €29,13 €
722,85 €40,34 €763,18 €

Saturday, September 4, 2010

Buying some more components

I've ordered some more parts for my mendel. The hybrid thermal barrier that reifsnyderb is selling seemed to be better than the regular nozzle, so I ordered one from him together with a barrel and nozzle. I hope I made the right choice on that one, as it is more expensive than the 12€ default one mendel-parts is selling.

I've also asked if it will be possible to control a heated bed with the generation 6 electronics. It seems that there will come an addon to make this possible in the future, which would also require new firmware. I decided not to wait for the addon, as the electronics themselves are not even released.

Scheme for the thermostat
(Click to enlarge)
I searched for a cheap thermostat and found one I could make myself. Unfortunately international shipping was expensive, so I had to find an other seller of the components. I have no idea how these electronics work, but as it was only 10$ for the components and 4$ shipping at, I decided to try and make it. You can see the scheme in the picture on the right. I made it a little easyer to read and added the values of the components on the scheme. In case you want to try to make one too, I have listed everything I bought in the table below. There are cheaper alternatives on their site for some of these, like the trimpot, but I decided to go for these anyway. I'll make a new post telling whether it worked or not once I have everything assembled. As testing it requires building the whole machine, this might take a while.

CERM5K5k 1/2W Vert. Square Cermet Pot1,311,3
TL431CLPTL431CLP Program Precision Reference0,3510,35
LM358NLM358N - Low Power Dual Op Amp0,2510,25
LED3GGreen 3mm Round LED0,110,1
2SA10152SA1015 PNP General Purpose Transistor0,0510,05
1N41481N4148 100V 200mA General Purpose Diode0,220,4
1N40021N4002 100V 1A General Purpose Diode0,0520,1
1N9641N964 13V 400mW Zener Diode0,110,1
R010KMF10kohm 1/4W 1% Metal Film Resistor (10)0,210,2
R0047MMF4.7Mohm 1/4W 1% Metal Film Resistor (10)0,210,2
R0012KMF1.2kohm 1/4W 1% Metal Film Resistor (10)0,210,2
R001KMF1kohm 1/4W 1% Metal Film Resistor (10)0,210,2
R033R1W33ohm 1W 5% Carbon Film Resistor (10)0,410,4
C010UC0.01uF 50V Ceramic Capacitor0,0510,05
C470U16E470uF 16V Radial Electrolytic Capacitor0,1210,12
ICS88 Pin IC Socket0,0410,04
LM35DZLM35DZ - Precision C. Temp Sensor1,9511,95
JQC-21FF-12SPDT 12V 10A PCB Relay1,1511,15
ROCKERRNDBL10Black SPST Round Rocket Switch0,410,4
HEADS88 Pin .100 Straight Male Headers0,710,7
PROTO777Prototyping Board - 7771,511,5
DCCHM52.5mm PC Mount Male0,210,2

At this moment I've spend a little over 500€ on components and shipping costs. I still have to buy the electronics, motors and some smaller parts. I think the total costs will be just below 800€, including the heated bed. It's a little more expensive then the laser cut Mendel from BotMill, but a lot cheaper then their unassembled Mendel. So it was worth looking around for beter deals.

Wednesday, September 1, 2010

Blog Layout

I have been working on the layout of my new blog. I took one of those standard templates and changed the colors and html a little. Normally I make my own layouts, but this was just so much faster, and the result looks just as good. The only downsides on borrowing other peoples work is I don't have the fun of making it, and the tiny reference on the bottom showing that I didn't make it. I suppose that isn't too bad. I can still make my own custom layout later on.

I tried to make something that matches the layout of my homepage. ( The layout there has been made by me, without having to borrow anything. I changed the background color of the posts to something that is a little easier to read than the gray-on-blue from my site.
I don't like sites with big background images or too flashy backgrounds, so I don't add them on my own sites, as you might have noticed. A vague drawing on both sides of the page is about the limit of what is still acceptable for me. But a background image is still way better than those new ugly flash-sites with things flying all over the screen.
If you don't know what I mean, just look at They clearly put a lot of work in their site, but the result is just awful with the flashy green background, auto-starting music and opening scrolls whenever I dare to click a button. What a shame that such a good game has such a bad website.

Anyway, enough about other sites, this was about what I changed here. Apart from the changed colors, I also made a header. I didn't have much time, so the only thing I could come up with was some text with a little glow effect on it. I'm not satisfied with the result, but it will have to do for now. I removed the standard white line around the header, as it didn't look good at all. It took me longer than expected to find where in the code I had to add something to center the image. Apparently I had to tick a box to show the full code. Once I found that box, it was easy to find the <!--Show the image only--> tag and change the code underneath it. Always nice to adjust documented code. :-)

You might also have noticed that I added some ads in the lower part of the sidebar. It doesn't cost the viewer any money to look at them, so it can't be that bad. If you find them annoying, feel free to use ad-blocking extensions like Adblock Plus for Firefox or Adblock for Chrome. I hope most of the people that don't like ads are already using that kind of software.

That's about everything I did today. Those are probably not the things you are reading this blog for, but I hope it will make my coming posts more appealing to read.

Tuesday, August 31, 2010


Hello, and welcome to my new blog. First of all I'd like to say that English isn't my first language, but I decided to make this blog in English, so it would be accessible to more people. So don't expect a literary masterpiece.

A little more about myself: I am 22 year old student and live in Belgium. I'm currently studying computer science at the K.U.Leuven. I do some web-developing in my free time. The biggest site I help working on is unicreatures. I also like to assemble and modify computers for myself and for friends.

A few weeks ago I found this site It is a community project about making a self-replicating 3D printer. I really liked the concept and started reading more about it. I have a few drawers full of old pc-parts at home, and I like assembling and upgrading my computer. This RepRap however would be a lot bigger and harder to make, and has much more potential for upgrading. Sounds like fun.

I quickly realized however that it would be expensive to buy all the parts, so I started searching for the cheapest parts. I also wanted them to be of acceptable quality. To give an example: some of the plastic parts sell for under 100€, but it looks like they will fall apart within a month. That would just ruin all the fun, so I decided to buy the items somewhere in the middle of the price range. I ordered the plastic parts from nophead and the other hardware from mendel-parts. I asked both of them to wait a little with the shipping, so the items should arrive here around 13 September. I haven't ordered the electronics and motors yet, because it looks like mendel-parts will have some cheaper and less complicated electronics coming soon. 

Today then I decided to make a blog about my progression with the project. I plan to modify my RepRap in the future, hopefully improving it that way. Maybe my experiences could be useful to others, and this blog looked like the best form of communication to the rest of the world. I'll try to post updates with pictures whenever I do things on the project. For now though, my recreation time is over and I'm going to study a little more for my re-examinations. See you soon.