Some constructive criticism on the experience of finding what I need to know.

Hello

I just received my Mendel Kit which is excellent, and I'm very happy and excited about it.

Now I have done quite a bit of research before it arrived so I had a general idea of how it all goes. But as someone who is entirely new to doing this I thought I would make this thread to log my experience and see where newcomers to building them might have issues.

I might be a little mean and maybe naive in this thread deliberately so pleas don't get all confrontational. It is meant to show how things can seem bewildering and could easily be improved upon.

So far I have not been able to find some relevant information with ease. I'm thinking perhaps we as a community need to improve the situation quite a bit.

To give an example the first thing I need to do is clean the plastics. Now there is very nice videos showing how to do this.

But the first thing I wanted to find out is what size holes are supposed to be where so I can clean them out the correct size. This may seem silly but a 3.5 mm and 4 mm almost look the same. As do a 7mm and 8mm. And it is not at all obvious to someone who has not built one what sizes go where. So I went looking for plans. Simple drawing I could reference to see which holes were what size. I did find some on the wiki but they were in English not metric and are overly confusing for the purpose.

This is actually really annoying. It's taking me longer to check the sizes on some 3D drawings I found then it does to clean the parts. I'm sure there is the relevant information somewhere but I have not found it as yet. Which also means somebody else probably can't find it either.

It has annoyed me so much that I'm taking photos of all the parts as I go and intend to then label the holes on them so there is a simple quick photo guide that tells me (And other people.) what size to ream the holes. I want to make a PDF out of them. Something simple like this would save me ages of checking before I do each part.

I can easily find drawings on the assembly. And I feel really stupid that I'm writing this but this is what I'm finding on starting too build.

Anybody else found this or am I the moaning idiot out of everybody here?

Edited 1 time(s). Last edit at 04/22/2011 03:03PM by Madkite.

The easy way to find the holes sizes is to look at the build instructions to see what goes into the holes.

Here is guide to the sizes: [hydraraptor.blogspot.com]. I now print the holes the correct size so parts from me do not need reaming or cleaning up.

Edited 1 time(s). Last edit at 04/22/2011 03:31PM by nophead.

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[www.hydraraptor.blogspot.com]

It has annoyed me so much that I'm taking photos of all the parts as I go and intend to then label the holes on them so there is a simple quick photo guide that tells me (And other people.) what size to ream the holes. I want to make a PDF out of them. Something simple like this would save me ages of checking before I do each part.

If you could embed those photos in the wiki that would be an elegant fix. Thank you.

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

I have experienced similar frustrations and am looking forward to seeing your photos and any other information you post. I was trying to get a set of drawings of the parts so I could machine them up, but ended up scrapping the idea through frustration. Everything is available as an stl file but nobody seems to have made available other formats.
I have also struggled to find consistency with BOM's.
I hope your idea comes off, it would be great for any newcomer to be able to view and understand it all easier.
I must add that I have found this site very friendly and helpfull.

As a rule, if you need to drill out a hole, start out small, and work your way up to the right size. Unless there are problems with the parts, drilling out holes is not normally required. This usually indicates that the extruder is running too fast given the layer thickness, or the axis calibration is off a little (or a lot).

I use the small blade of my Swiss Army Knife to clean up parts. It's actually very relaxing, though it seems that PLA in particular makes my hands dry.

ABS plastic is known to be a polyamide that is hygroscopic meaning it expands with water in air and can expand greater than .1% per day of its size in area when exposed to moist air. So ABS plastic can be sized, and then shipped to you, and it will need to be resized again. The best method to ship is in an airtight bag.

Just a quick comment on drilling out the holes. If you use a power drill, you could drill into the plastic with the drill spinning backwards to the cut of the drill bit. This allows the part to be drilled into clean. The other way tends to rip the plastic apart, and makes a mess. Many people also suggest hand drilling only. Also never hold the part in your hand when you drill into it. The plastic part can catch the drill bit and pull out of your hand. If the plastic is not completely smooth your in for some missing skin, or a serious injury.

Just some suggestions. IMHO

Thanks.

Don't worry I know how to not mess them up. I am am a electromechanical engineer and have been messing about with tools since I was four. I'm just pretending to be a bit more unfamiliar with it all than I really am.

They are not parts I printed but they are quite good. What I was expecting really.

I'm taking the photos as I go so it will be a little while. I'm cleaning the bits in between doing things like fitting a new windscreen seal to my Moggy. At the moment I'm writing on the parts with a sharpie what the sizes are as my computer is not in my shed. It also reminds me when I come to label the photos.

Now there's a thought. A shed computer. Add a chair and a few other conveniences and its paradise.

I'm not sure but I might be able to turn the stl's in to plans. I would have to try with the various programs I have and it would take a while. If I can do it then I will make them JPEG pictures so anyone can view them. But that's another project.

Madkite: I understand your frustration completely, finding the best information can be VERY difficult in this community. The Wiki is full of flawed and often contradictory information (assuming you can find what you are looking for at all), and finding the info on Google can be just as bad.

The one source of info that is usually quick, easy and reasonably reliable is the RepRap IRC channel. A number of very experienced people hang out there regularly, and are happy to try to answer your questions. It's not perfect, but it is the best source of info that I have found.

I'm not sure but I might be able to turn the stl's in to plans. I would have to try with the various programs I have and it would take a while. If I can do it then I will make them JPEG pictures so anyone can view them. But that's another project.

You may find one of these helpful:
http://reprap.org/wiki/Category:Mendel_Mechanical_Drawings

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

Madkite,

I had precisely the same problem as you and had precisely the same idea. I finished my mechnical build this weekend (though I temporarly broke my extruder while trying to get it to work so progress has stalled for a few days).

I finished my 'hole size' sheet yesterday - so, haven't uploaded it yet. I may take a few days till I get round to putting on my blog site so here's the basic material (99% finshed). I think they are correct and consistent but please let me know of any stupid mistakes I've made.

And a definite nod to Nophead for his help. I asked a similar question and he pointed me at his advice too (which I've integrated into the attached files)

Cheers

Pete

That's nice work Flackster.

I have all my photos taken now. And an almost complete Mendel. I have to say I have been enjoying the build. From the moment I finish work till I realise I havent eaten I have been building almost obsessively.

Would have updated here earlier but it has grabbed my attention like nothing else. And I had a date tonight So I have been a little preoccupied.

I'm going to just have a quick guide and label each of the pictures with the hole sizes pointing at the holes. I wanted a quick reference guide I could take and look at in the shed. And as some of the parts I had were not fantastic and it made it impossible to tell what size you needed without checking.

My plastic will not come till next week so I hopefully may have time to compile the quick guide.

Then I'm off to design my mod to double the X & Y accuracy. I have acquired all the auxiliary hardware required so I'm all set to do it. Will publish if it is not a complete disaster. And I'm fairly confident on this one.

After that I have something rather radical and novel to try. I don't want to say too much yet but if it all works (It may be a big IF.) then printing in metal and plastic from the same depositor during one print may well be possible. The technology is established for this and it all depends on my adapting it for a new purpose. luckily it crosses over with an aria of research I have been fascinated by for years. And if this works it will need no fancy gasses or materials though it does need accurate parts. And I foresee quite a few hurdles to jump yet.

So I'm going all blue sky later this year. Hopefully it will be worth the effort.

Oh and I decided to name my machine Bertha. I doubt many people will get that but it was my favorite when I was 4 and I thought it was appropriate.

Now I need to sleep.

Bertha just happens to be my laptop's name... I don't get it though, what was your favorite when you where four?

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I'm building it with Baling Wire

I presume he is refering to this: Bertha TV Series.

Not familiar with it myself, though I do remember Postman Pat which was done by the same company.

"The show focused on an extraordinarily capable factory machine named Bertha. In each episode there would be some sort of daily crisis involved in factory production. With the help of her friends (the factory workers), Bertha invariably solves the problems."

Going by that description I would say it is an extremely fitting name for a reprap bot

Hello again.

My photo compilation is coming along nicely and as I have nothing better to do like print things as I have no plastic, I decided to test the X Y accuracy.

I crudely rigged up my long travel clock gauge on Bertha and you can watch the results in this video which like all videos I make I find very embarrassing. I have not tested the Z as the would seem to be very accurate in comparison but I can try if you wish.

And why do I always sound so posh? Do I really sound like that!

[www.youtube.com]

Ha, I got the embed thingy to work .Take that forum coding.

Madkite,

It all looks as if it's coming along very nicely - excellent stuff!

I've finally updated my website now (including my RP part to hole size, etc mapping) - [www.flackster.me.uk]

I'll be interested to see your pictures once they're done. Damn fine idea.

Cheers

Pete

Cheers. I'm going for the video blog if anything. Mainly because I'm rubbish at typing. Like your blog though. Blogs are the only places I have found very useful and simple guides to changing the steps per mm.

My slightly tongue in cheek guide is hopefully going to be finished by the end of the weekend. Should get it all put together tomorrow and then its just checking. Mainly checking my typing. Not that anything I write really detracts from the value of the pictures. Its just so simple.

I wanted to test the accuracy so I have something to compare too when I finish the modification. I need to get it printing at least semi well to make the parts first and I should be getting plastic on Saturday. So maybe in a week or two I will have it with an X Y accuracy down to .05mm instead of .1mm. Think a lot of people will be interested in making it more accurate. It's the thing I have seen criticised quite often.

[www.mediafire.com] Pdf file

[www.mediafire.com] Word file

Ok I finished my not to serious guide so you too can print it out and have it in your shed. I added the original word document so you can edit it and fix or add stuff as you think necessary. So everyone is free to add advice or guides to doing other stuff it and stick it back up.

Let me know the links are working and you can download it.

And before you criticise too much it is free. And writing is not my strong suit.

Now I'm off to finish designing my parts for the X Y mod. And when my plastic eventually arrives make it.

And someone who I thanked on YouTube kindly made a video on changing the Gen6 firmware which was extremely helpful. I am now confident I can do it having tried the software all out.

If we make how too videos and stick them in the wiki it will make it so much easier to find stuff. You can learn so much more by watching and being shown in a tenth of the time.

If you like the guide then I will try to work out how to put it on the wiki.

Update

Have been experimenting with printing in ABS. And had a few initial disasters. I think the x carriage really needs to be made of ABS as mind got warm after a while when I first used it for a few hours. This made the lower half catastrophically warp and all the bolts that held the barrings come loose. The warming also made the belt clamps come loose and the tall bit they clamp on too break!

I fixed it all however. I unwrapped the lower carriage by placing it on the heated bed and used pegs, weights and spring clamps to pull it back in to shape as it got warm. I then let it all cool, and it was fairly flat. Usabl anyway. I then plastic welded the split part back together with a screwdriver I intermittently heated up with a small blowlamp. I have now put a piece of thick aluminium sheet on it and made steel clamp blocks. I also installed a fan to gently suck the hot air away from it.

I have run the Bertha for a couple of days now with no problems with these modifications.

So now I have started to get to grips with skeinforge. So I will start printing with that very soon. I did manage to print a spire lower X carriage completely solidly infilled and some of the parts for my modification. And a bust of Beethoven though it looks like he is a bit diseases.

I' also going to try a polycarbonate print bed. I know from others that the parts stick well. Too well in fact. So I'm going to experiment with methods of loosening them up. I also have some cogetherm to try! Not much hope for it but its there so why not.

More on the mod to follow soon.

More progress.

I will make a video soon as I'm about to install my upgrades. The polycarbonate bed works really well though getting parts off can be a bit of a struggle. I need to glue it to something rigid as when printing large parts it pulled up the 3mm polycarbonate sheet! So that's part of the upgrade too.

Been playing with skinforge and got some reasonable results. I found I had to set up the lash to make some of the parts print properly. Doing that removed a lot of errors. I still have tuning to do but will wait till after I have modded as it will have to be calibrated.

This is the alpha test of mu accuracy's doubling mod. As you can see I have made the belt system in to a double pulley system so the stepper motors have to turn twice as much to move at the same speed. This does not seem to be a problem however. Especially as the only parts moving at twice the speed are the motor armature and the belt. These way very little and so have a small mass to start and stop. Plus the motor has half the torque load on it. But the carriage can now move at the same speed with twice the accuracy.

The X axis parts are all perfect but the Y axis clamps need some tweaks before I can publish the STL's due to a few unforeseen collision points.

Also print tests need to be done but it looks promising.

This is an excellent idea! Good work. I prefer leadscrews for accuracy, but they are very expensive for these class of machines, and direct drive belts always seem a bit overgeared. But this is a fantastic compromise. Though I'm sure there will be some who bemoan the expense of even longer belts!

Thanks. I thought it up before I even started to build my Mendel.

I got my belts from here.

[www.beltingonline.com]

Only costs about £15 to £20 for 5 meters of open belting. With all the other parts probably about £30 in total.

The belts are only about half as long again than they were. I did wonder if this would be a problem but with half the load on them, spring does not seem to be any trouble.

Lead screws are ok but I think the precision of the construction and the technical skill required get that precious is too much for the current situation. They would also be very expensive and hard to make work fast too. This is really simple to do and involves nothing that you already wouldn't have done if you have built the machine. The print speed also remains the same which is a real bonus as I did wonder if I would need to slow it down.

This brings the precision to .05mm which is quite small. I don't think much more precision will make any improvement without much better extruders.

I have finished testing and it works really well.

It up here.

[www.thingiverse.com]

Enjoy.

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Make your Mendel twice as accurate.
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