Wednesday, 26 March 2014

Prusa i3 Y axis length for box version

The issue

I got to the point in my build when its time to attach the Y axis to the frame and noticed something very off between the guide and my build.

My Y axis was a fair bit shorter then the one shown in the guide, which meant if I had the motor at the back, as per the guide, I would lose a fair amount of print area.


Looking around the forums I noticed I wasn't the only one with the issue and it was caused by a difference between the official github and the wiki.
The wiki stating 370mm smooth rods with threaded rod to match and the github stating 405mm smooth rods and threaded rod to match.

The difference (35mm) is roughly the size of the mounted Y axis motor and the print area lost if mounted at the back.


Move the motor to the front, remove the washer and nut from the idler side and move the belt tensioner on the bed plate.
Moving the motor to the front gains a few cm's, removing the extra bolt and washer gains roughly 1 cm and moving the belt tensioner should regain the last few cm/mm.

Dragonfly DIY's blog outlines the changes.

Its still not ideal however as its its re-drilling the print bed wood, removes the supporting washer holding the Y axis to the frame, doesn't look as clean (you have wires going from the very front to the back along the Y axis) and leaves little room for error/tweaking.

As I've already got the correct length threaded and smooth rod on hand from my original Prusa I will order some more GT2 belt (2m so I have some spare) and will re-build the Y axis later.
For the time being however 150x200x200 (mm of course) should be enough to allow me print some basic things to improve my setup (RAMPS mount, RasPi mount, auto bed levelling parts and spool holder)

Tuesday, 25 March 2014

Prusa i1 to i3 upgrade - Build day 4

Real date 16/03/2014
As with Day 3 I was feeling terrible, so didn't spend as much time as I had planned (was aiming to be printing Saturday night).

As previously mentioned I'm following this guide and will only be documenting things I have trouble with or do which the guide doesn't state.

Z Axis

The motor and Z axis holders have 3 holes on one side and only 2 one the other.
Do not drill the blanked side out.

As you can see adding a screw in into the frame at that position wouldn't make sense.
I suspect the generation script doesn't fully remove the extra screw hole which is used on another variant.

Once you have the motor holder and top rod holder in place, remove the screws from the top piece.
This isn't show or said in the guide, but you'll need to be able to add the X axis to the frame.

X axis

The assembly is one of the easiest parts, however getting the Z axis rod to move smoothly throught the nut is a little tricky.
In the end I used a 6mm drill be to enlarge the hole, this means the 5mm threaded rod doesn't snag or attach to anything but the washer.
I wouldn't go any larger then 6mm as the M5 nut would run the risk of slipping out.

Note I reused one of the 608zz bearings for the X axis and the belt looks like its not going to slip. However the is a gap so I will be on my list of parts to order.


I got a new extruder a freebie from 3DPrinterPunk because they forgot to send me the Y corners.
Its a Herringbone Greg's accessable extuder.
The assembly is pretty much the same as Wades only with less parts which is always nice.

The thing to note is the extruder uses a 17mm piece to hold the idler bearing in place as opposed a 20mm piece used in my old Wade.
Its worth noting with the compact X carriage and this extuder you can't double the nut at this side as the clearance is small and the second nut will catch on the X carriage.

End of Day 4

Getting the belts right on the X carriage took a while as did getting the Z axis threaded rod moving smoothly (I started with a 3mm drill bit and worked upto 6mm).
I've not documented it, however about 1 hour of the build time was actually disassembling my old Prusa as I needed the bearings for the extruder (I used the extruder bearings for the X and Y axis).
Prusa i1 frame vs Prusa i3 frame

Days build time: ~2 hour
Total build time: ~6 hours

Wednesday, 19 March 2014

Prusa i1 to i3 upgrade - Build day 3

I'm a bit backlogged on my posts as I got a horrible cold the day after build day 2 (Friday) which has only just started to fade. I did bits and pieces but never spent any real time.

As previously mentioned I'm following this guide and will only be documenting things I have trouble with or do which the guide doesn't state.

Print bed - Smooth rod distance

It all looked very straight forward until it came to check it moved smoothly, as attaching the bed involves drilling and screws it moved slightly.
After a few attempts at tweaking the width to get it moving smoothly I decided to put down the spanners and work out the optimal distance myself.
Some amazing photoshop skill

Add the blue lengths
Add the green lengths then half them (this gives you the center of the plastic part which should be the center of the bearing).
Add the result of the above values then take this away from the yellow/orange value.
yellow - ((blue + blue) + ((green + green)/2))
This gives you the distance between the center of the top and bottom bearings. To get the gap between the smooth rods just minus the width of a smooth rod.

Measure the width of a Y corner piece. From this value minus the width of the smooth rod.

Take this value from the distance calculated from the printbed.
This is the width between each corner piece.


Belt holder

Following the guide its pretty straight forward however if your belt holder is loose and doesn't hold the belt when its tight the guide recommends "shim it with an M3 washer or a piece of card".
Which in simple turns means jam small washer(s) or hard peice(s) of card under the belt until it doesn't slip.
Like so

End of Day 3

The rugby six nations grand final (unlucky England, well played Ireland) was on and I felt very rough so this is all as I did on day three.

Days build time: ~1 hour*
Total build time: ~4 hours

I did the work between matches and during half time so could have been 1h30m or 45m as I wasn't paying much attention.

Thursday, 13 March 2014

Prusa i1 to i3 upgrade - Build day 2

Due to the issue with missing plastic parts I had a day break between build days.

True to my jump to section I like the look of style instead of attaching the last piece of wood to the frame I jumped to the Y axis.

As previously mentioned I'm following this guide and will only be documenting things I have trouble with or do which the guide doesn't state.

Y Axis corner blocks - aka the missing Arduino box

The assembly is pretty straight forward, however the guide states to use the Arduino box and gives no dimensions of it.
As my Arduino's are clones (much cheaper and the same functionality) they didn't come in the official box and the box they did come in has long been binned.

I checked around and according to the official RepRap forums its purely used as a spacer to ensure the smooth rods are level. So referrencing the image I looked around for something similar size and found a Raspberry Pi box and used it.
I measured the box and it was slightly (~0.1m) over 12cm in width.

I found a quick way to ensure booth sides are the same width is to attach a M8 bolt (or piece of M8 threaded rod) through one side and attach a nut.
The alignment both using the same box (or callipers).
The picture is poor quality, but you can see the bolt on the left corner piece.
As well the the Raspberry Pi box.

This shows the bolt a little better.

Smooth rods

The smooth rods referenced in the guide for the Y axis are actually the shortest of the smooth rods.
The guide is a little confusing as it references them as the long smooth rods.

If you threaded rods are line mine, only slightly (5cm to 10cm) longer then the shortest smooth rods its best to have the corner pieces at the very ends of the threaded rod, otherwise you'll be adjusting there location until they are.
Contracory to the guide I its easier to put the bearings on the smooth rods when you first insert them as they are clip fit pieces and are a pain to get out without messing up the alignment.

Y axis idler

The guide is using 624zz bearings while I had planed to reuse my 608zz bearings so I had to make slight adjustment.
Below is the setup I'll be trying first.
Flash seemed to make the image clearer, but darker at the same time

Its M8 bolt, washer, plastic, mudguard washer, 608zz bearing, mudguard washer, plastic, washer, two M8 bolts.
As there isn't room for standard washers I used the two nuts to keep it in place while allowing the bearing to turn.

End of Day 2

At this point my niece had gone to bed and I didn't want to run the risk of waking her up by drilling so I called it a day.

My desk/workbench is filling up, but the build is coming along nicely.

If everything goes well and I don't get any hickups I should be ready to start printing this weekend.

Days build time: ~1 hour
Total build time: ~3 hours

Wednesday, 12 March 2014

Prusa i1 to i3 upgrade - Build day 1

I'm not going to document ever step as most of them are pretty straight forward or a case of doing the same thing on the opposite side or again a different section.
I followed this visual guide which is for the same version (box) and using a similar electronic setup.

As I'm never one to completely follow instructions I skipped to the frame assembly first as it relies on the heavier tools and can be done independently of the other parts.
I couldn't find my countersink so just used a ~10mm drill bit in its place.

The L sections

These are pretty simple as long as you use clamps to hold the pieces together.
Before you clamp them and get them in position mark the half way point on the board as this will help get the middle screw in the center.

Offset the top and bottom screws by 2cm to 3cm.

The base

This is a little tricky as it requires a 3mm spacer and the new piece of wood has a habit of moving when you drill it.
In hindsight I would highly recommend you use clamps.
On the plus side 3mm filament is, well, 3mm so its ideal as a spacer for this job.
Note the drill battery sitting on the spacer to keep it level.

End of day 1

I forgot to charge the drill batteries prior to commencing the build so I ran out of battery for the last piece of wood (for the frame).
As I'm missing plastic parts there is nothing I can do for the time being.

Days build time: ~2 hours*
Total build time: ~2 hours
*Includes switching between 3 drill bits, sorting and arranging the parts.

Just a side note the frame appears much larger then I was expecting. I'll take a photo of it and the Prusa i3 frame side by side once I add the last piece.

Prusa i1 to i3 upgrade - The old boy

Before I started to strip down my old Prusa I thought I'd take a few quick photos for reference and so show the wear/age of it.

Yes its a mess
 The blue parts are replacement parts. The black stuff under the printer was an experiment I planning on trialling, but never got round to. Its high density foam designed for noise isolation, the idea was it would absorb some of the vibrations and reduce wobbly because of this.

You can see the cracking near the washer which if adjusted or removed would likely cause it to break in two (like the endstop did).

Tuesday, 11 March 2014

Prusa i1 to i3 upgrade - Parts arrived

As I mentioned in my previous post (well previous real post) the plastic parts arrived on the 1st (01/03/2014) and the hardware was delayed. So between the two deliveries I've not been able to do too much in the way of the i3 upgrade.
I'd cleaned a section of my room which I can dedicate to the printer and been frequenting the official forums and Reddit sub forums (3D printing and RepRap) in order to get myself upto date with the latest advances (in RepRap terms) as well as any common issues.
I also bit the bullet and ordered a SG90 micro servo for the Z probe upgrade I spoke about. I literally just picked the cheapest UK based seller who had good reviews and was selling the complete unit (arms and screws included) on eBay.

The Plastic Parts

I bought my plastic parts from 3DPrinterPunk for the reasons I outlined in my previous post (cheapest and the time and prints looked good).
The parts came well packaged with lots of packing peanuts as well as free cable ties and filament (which as you can see in the photo has the temperature as well).

Here's a photo of it all unpacked, please note the lm8uu's I added and didn't come with the plastic parts.
Sorry about the picture quality I was stood in front of the lights
Anyone with a keen eye will notice two things which don't match most printed part kits.

Firstly the little square parts (there should be 10 showing in the photo but I was inspecting them), they are cable tie holders and the central hole allows you to attach it to the wood via a screw.

Secondly there are 4 pieces missing. As its my first i3 build I didn't even look twice at the parts until I was using them in the build, at which point I noticed the missing parts (Y axis corners).

3DPrinterPunk was great a great help, he emailed me a list of parts and helped identify the missing ones (from the above photo) and is sending me the parts along side a free ABS extruder as an apology. The email exchange all happened after 10pm at night and was all resolved in about half a dozen emails.
That's some serious customer service and while the free extruder is a little much I'm not going to object.


I ordered my hardware (wood, rods, fastenings, bearings and belt kit) from Greg Colbourn via eMakerShop.
Freshly unpacked
 The parts came well packaged and all the fastenings were nicely labelled.

So the build begins.