Resources

So while I'm not making much progress I thought I would write a bit about the resources I have been using. The main one which helped a lot during the build phase was

• http://reprap.org/wiki/Mendel 

There you can find information on what you need to build a reprap, how to build it and how to test it. You can also find links to most of the firmware needed for the electronics and the arduino software needed to edit the firmware and upload it.

The only thing that I found hard to find was the details of the particular type of electronics I had. I bought a complete set, the TechZone Remix which is a 3rd generation set. The two wiki links I have been using are:

• http://reprap.org/wiki/Generation_3_Electronics/Tech_Zone_Remix

• http://reprap.org/wiki/Generation_3_Electronics/Tech_Zone_Remix/How_to

Neither are particularly complete but they were very helpful when assembling/testing the electronics and in particular when flashing the firmware.

Other than that the arduino site (http://www.arduino.cc/) was probably the only other place I turned to for information.

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Still here

It's been a bit of a busy month but I am still here, working on the reprap when I have a few moments spare time. I managed to get some firmware onto the extruder which was nowhere near as simple as I expected, but I got there in the end with the aid of some helpful bloggers. The secret, hold the reset button on the board for 10seconds after you clicked the program button from the arduino software. Something to do with different types of atmega chips, I didn't read in to it too deeply as I was just rather happy it worked!

Apart from that I still need to finish the cable routing and order a replacement component for an optoswitch. The optoswitch I managed to break by connecting it the wrong way to power and ground, I'd like to say it wasn't my fault but it turned out I was using the wrong version of the motherboard schematics as a reference. Never mind I found a replacement on Farnel (optoswitch) so all is good.

I leave you with a picture of the wiring before I had a go at tidying it:

I'm happy to say that it looks a fair bit tidier now!

More electronics fiddling

Some more progress, I've had a chance to test the rest of the electronics (yay). There seems to be some kinda problem with the extruder board, I cant program it as it keep complaining about sync issues. So I've left that for the moment. Instead I've been working on testing all the steppers/stepper drivers etc. Heres a quick video of each of the axis moving.

Once I had tested those, I moved on to the opto end-stops. I only had time to test the Y axis one, but that worked fine (video below). However I did blow up one of the end-stops in the process which will teach me not to trust circuit diagrams and just use a multimeter!

So tomorrow I will try and get the x end-stop in place then maybe try and repair the one I broke. Then I will have to sort out the extruder driver board, not sure where to start with it but hopefully it's fixable.

First play with electronics

So I had time for a quick play today, I managed to upload the firmware to the motherboard and ran a test using the Reprap software to talk to it. It wasn't, however, a pain free experience. The instructions were poor at best, stable versions of bits of code weren't easily available and it didn't play nicely with windows 7 (didn't really expect it to though).

Anyway after fiddling around on my xp netbook I got it working... sort of. It seems that the motherboard firmware I uploaded, when asked for the the extruder temperature (M105), reported the extruder temp AND the heated bed temp. Well the Reprap software didn't like that, not one bit. There were NullPointerExceptions and IntegerExceptions everywhere as it clearly tried to parse "0 B:0" as an int. Luckily being open source, and having the source at hand, I removed the offending code from the firmware, reuploaded and - tada all was well. I was going to test more of the electronics but, that requires making up some cables to the right length, so that will be a job for monday.

The usb/serial adapter and motherboard with the happy yellow light of workingness.

Look it works, g-code commands being sent and replies being received, hurrah!

Electronics are here!

So finally the electronics are here! Everything seems to be intact, despite the box looking like it had been driven over. Time to resume work I on the reprap I think!

Obligatory pictures:

Electronics

So I could a nice note from Royal Mail today asking me to pay £30.95 worth of "Customs charge", while that in itself is rather annoying, what I'm hoping is that it's the electronics finally getting here! We shall see.

Still no electronics

So a month after I got the shipping information the USPS page still only says:


Detailed Results:
Acceptance, April 23, 2010, 2:06 pm, BLACKFOOT, ID 83221

Electronic Shipping Info Received, April 22, 2010

Which is... %$^$ing annoying, to say the least. I've been rather busy lately so I've not had a chance to phone USPS yet, that's a job for tomorrow, I'm curious to know whats going on.

Mechanical construction finished

It's finished! Well sort of, I've not fitted the bed and I don't have any electronics yet but it's getting there. The electronics (or at least some of them) should be arriving soon, I got some of them from ebay so here's hoping they all turn up ok.  All that's left to do while waiting for more parts is add some thread locker in a few places.

I will try and post a video later so I can show how the various axis move.

Z axis

Well after a bit of delay, here is the next part of the build. The z axis, although made up of only a few bits, was one of the fiddly-est parts of the build.  Here you can see one of the z axis threaded rods in its bearing assembly.

The underside of the assembly has a cog on that is rotated by the z axis belt, this ensures that both z rods rotated at exactly the same rate. Tightening the belt so that it was tight enough that each step from the stepper motor produced a movement in the z axis but loose enough that the stepper ran smoothly was frankly a pain in the arse. I think a different tensioning mechanism would be beneficial.
However once the z axis is done the only thing remaining is to mount the x axis. But before I do that here are a few pics of the frame so far.

The next step took a while, basically the x axis needed to be fitted. This involved loosening a few bolts, the z axis guide bars, z threaded rods/gear assemblies, sliding the x axis on, screwing the threaded rods into the trapped nuts (in the x axis), tightening everything and fitting the belt. All in all it took quite a while to get it to the point that the x axis was level and z axis would move up and down smoothly and easily. Here are a few shots of it with x axis fitted (if the x axis motor looks the wrong way up then that's because it is! I was testing an idea at the time of the photos).

Since it's rather late I will save the photos of the finished mendel for another day, time for a nice cup of tea. How quintessentially british! 

Frame and a few fixes

Quite a long post today, as I had a fair bit of fixing to do. A few people pointed out that my x-axis wasn't quite right, it turned out I had put the carriage on upside-down. Luckily it was just a case of loosening a few bolts, taking off one end and the carriage and putting them back on the right way round! Here is how it looks now, carriage on the top and x-axis stepper pointing down. 

I also tightened the belt, I had left it loose when test fitting it and forgot to tighten it! Once that was done it was on to fix number 2 or 3 or 4 or something. One of the RP parts that holds one of the bearings for the z-axis was missing some holes, here is the part.

No idea why the holes are missing, it doesn't look like it failed print the holes properly just like it never tried, so never mind. Simple to fix though, pop it into a vice with the other RP clamp part as a guide.

20 seconds of drilling later, and its all fixed.


Now that's done, I can get cracking with the frame. All the nuts are finger tight at the moment as I will check distances/measurements once the frame is in one piece.

Here is the other half of the frame complete, just need to bolt them together now. I did have a bit of trouble getting the threaded rods through some of RP parts, but again it wasn't a big deal I just cleaned up the insides of the holes a bit with a file.

Bolting the two halves together was relatively pain free, the bearing assemblies for the y-axis belt are just loose fitted in the picture below as I hadn't broken out the ruler yet.

Just enough time to finish the frame off by adding the last two threaded rods. And all done, still need to check measurements, but that's for another day.

Here is my jig-stick :) made from a few bits of steel stuck together. I turned the ends down on a lathe to within about 1/10th of a mm of the jig lengths on the reprap wiki so it should be ok.

Finally a shot of my work-area (my carpet), as you can see I'm a tidy person.

And there you have it, I'm getting close to the end of the mechanical build. Now I need to fit the y-axis, attach the x-axis and z-axis, thread belts on and I should be very close to being done.

Y-axis

Time to crack on, so up next is the Y-axis. This is basically the "tray" that stuff is printed onto. Of all the parts it was the most annoying/fiddly to assembly, so many washers and bearings at funny angles.  Here you can see the two sets of bearing assemblies that the Y-bars slide through. The two blocks in the middle of the clear acrylic sheet are

belt clamps.

Here is a better view of the bearing assemblies, as you can see all funny angles. Getting all of the bearings to run smoothly and not foul on random bits of plastic was a pain, but once it was all tensioned it ran very smoothly.

The four bolts in the middle hold the purge plate and y-opto flag, but I don't have them yet :(

So that's another piece done, just the z-axis and frame to go!

X-axis

Now the building starts, the wiki recommended starting with the extruder, but I'm missing a few bits (nichrome wire etc) so I decided to start with the x-axis.  I started with the Z-axis bearing (the Z-axis guide bar runs through the two washers in the photo, while one of the threaded drive rods runs through a trapped nut).

I then moved on to the extruder carriage, you can see the extruder stepper mounted here (the black box).

Time for the other Z-bearing assembly, here you can see the top set of 3 bearings that trap the z-axis. The x-axis stepper and drive belt were next to be added.

Et voila! One X-axis fully assembled, the action is very smooth and it's a lot more rigid than I was expecting.

Here you can see the extruder carriage, and how it sits on the supporting rails.

A box appears

It's always nice when a parcel turns up, however I don't remember ordering any bananas...

But what's this? The box is completely lacking in bananas, instead someone has filled it with reprap parts, which is much better!

So many packets and bags, all neatly labeled.  Everything is there and in perfect condition which is impressive considering it came all the way from Hungary.

So now that it's all here time to start building, I'd just like to say thank you to Laszlo again for getting everything printed and shipped to me and for putting up with my constant stream of emails!

Hello!

Welcome to AberRap, yet another reprap blog! This blog will follow the construction, operation and hopefully tweaking and improving of a reprap Mendel. 

So what is a reprap Mendel? Well wikipedia says:

"The RepRap Project is an initiative aimed at creating a largely self-replicating machine which can be used for rapid prototyping and manufacturing. A rapid prototyper is a 3D printer that is able to fabricate three dimensional artifacts from a computer-based model.".

The Mendel is the second generation or "new and improved" version of the original Darwin reprap machine, it is less prone to jams and is basically "better, faster and stronger"! I got the mechanical parts (printed parts, studding, bars, nuts/bolts,belts and stepper motors) from Laszlo at http://blog.arcol.hu. If you are interested in making one yourself definitely drop him an email, he's a great guy and really helpful. 

Now that the obligatory introduction is done, on with the build!