Monday, 3 March 2014

Upgrading Prusa i1 to i3 - Parts

As I mentioned in my previous post my current Prusa (i1) is in a pretty bad way as far as the plastics are concerned. Due to the original Prusa being phased out it was either a case of get the parts custom printed or look into alternatives.
Given that my plan was to upgrade my Prusa a while back it seemed a little pointless getting custom printed parts then printing parts for a new printer myself. Both cost and timewise it wouldn't be too productive.
As I mentioned before I'd my eye on the Mendel90 however the parts aren't readily available compared to the Prusa i3.

Re-usable Parts

Each 3d printer is made up of segments, some of which are interchangeable some of which aren't so much.
Here's a quick run down:
FasteningsNuts, screws, boltsSome*
Bearings608zz and lm8uuYes**
RodsThreaded and smooth rodsSome***
Belts and pulleysT5, T2.5, GT2Yes
MainRamps, Gen6Yes
Stepper motorsNema17, Nema14Yes
Heated Print bedYes
Hot EndJ-Head, E3DYes
Main partsNo
ExtruderWades, GregsYes****

* Some of the fastenings will be re-usable however the newer Prusa (i3) has a few variants so double (and triple) check you have enough of each.
** If like mine they have been stood for a while its worth checking them and adding some lubricant
*** Like the fastenings there are a few different builds of the Prusa (i3) and they use slightly different rod lengths. If the rods are in good condition they should be fine to replace the M8 and 8mm rods for the new Prusa with a little cutting.
**** The extruder sits on the X carriage so should as long as there is room for it and the X carriage has mounting holes which match.

Which type/variant?

 As I previously mentioned there are a few different types/variants of the Prusa i3. The main three are as follows.
  • Laser cut - Wood
  • Laser cut - Aluminium
  • Boxed - Wood
Both of the laser cut versions use the single sheet style, this is to say the main Z axis only has one sheet/plate. The boxed version on the other hand uses multiple sheets on the Z axis.
While the laser cut versions are lighter and look a little more fancy they lack the extra rigidity of the boxed version, however the boxed version is a little more DIY with holes to be drilled.

For me a main factor is price which the boxed version wins at every time, while the laser cut versions require expensive machines the boxed version only requires basic tools and a little time. The difference is clear once you look up prices. Laser cut wood ~£40, laser cut aluminium £65, wood for the boxed version sub £10.

My plan


While I want to re-use as much as possible I don't want to risk damaging new parts because of old parts.
I also don't want to be going out and buying new/better parts within a week or so of getting printing.
For this reason I'm only reusing the electronics, bearings and (temporary) extruder.
I could reuse a lot of the threaded rods however the printer has been sat for a while and I suspect the rods will have a little curvature to them.


Instead of opting for a straight forward rebuild (admittedly I doubt its going to be completely straight forward anyway) I want to make a few long standing upgrades.

First the bearings all to lm8uu the original Prusa was focused on as much printable as possible so the base version relied on PLA bushings.
While good they didn't last too long and, in my experience, had a habit of coming loose.
With the Prusa i3 its all about print quality and stability so the PLA bushings got replaced with real bearings in the form of the lm8uu's (widely accepted as an upgrade option on the i1). So the lm8uu upgrade was part of the rebuild (but I'm still classing it as an upgrade).

Second upgrade I've been meaning to do is the belts and pulleys.
At the time of the original Prusa T5 were the norm, then T2.5 followed shortly after by the GT2. The T in T2.5 and T5 stands for timing, they were never designed to be used in the way RepRap'ers did. This was the reason they had issues with backlash and a few issues. The GT2 belts were designed for the actions of RepRaps and helped reduced the issues of the T belts, which of course helped improve the quality of the prints.

Lastly I'm looking into auto bed leveling.
With the original Prusa the bed needed leveling every print due to the vibrations adjusting not only the Z axis, but also the bolts and nuts on the print bed. Prusa i2 (or a heated bed upgrade) moved away from the spring setup which inproved things, but still wasn't ideal.
Around mid to end of last year it appears functionality was added to Marlin (firmware) for auto bed levelling as well as add-ons/upgrades which use a servo and microswitch. The microswitch allows the firmware get the levels while the servo lifts and lowers a arm with the microswitch on it (lifters to avoid damaging the prints). I've got a dozen spare microswitches and some old motors lying around so this will be my first non-bought upgrade.


A lot has changed since I started my original Prusa some of the suppliers have disappeared, some no longer stock the same items and others have grown.
Thingfarm, whom was my largest suppler last time, vanished not long after I got into the swing of things.
Luckily eBay still has a decent amount of suppliers, but now seems to be more focused around electronic and hardware as opposed to plastics and fillament.
A semi-new site for me is eMakerShop I used it for the heated bed supplier (Think3D) and its grown nicely in all areas.

For hardware I wanted I found the same seller was listed on both eBay and eMakerShop and was offering slightly different prices on each. Strangely enough a like for like was a few pence cheaper via eBay, its strange eMakerShop don't charge for listings, but eBay does.
With this in mind and the items I wanted not in a set kit, I requested a quote and it was nearly £10 lower then the items bought separately from either.

That was the hardware sorted now I needed the plastics, which is a lot more tricky then anyone new to RepRap would think. Good printed parts can be hard to come by and prices can change drastically depending on filament suppliers and demand.
With cost in mind I took a punt and did something I refused to last time. Picked the cheapest UK based supplier off eBay (link to seller). Unfortunately they only hand stock of the single sheet printed parts, luckily they supplied an email address, so I requested a quote. I got a nice reply quickly saying they had no stock, but could print me some within 24 to 32 hours for £19 delivered (note this is slightly cheaper then the eBay listings). Compared to the cost of my original printed parts at £75 +£7 P&P it was a world of difference, but worth a punt as I doubt I could get cheaper elsewhere.

After some quick math I noticed I was under budget (I had budgeted £100) so added the pre-cut wood from the eMakerShop seller for £10+£3 addition P&P.

The parts

Here's a quick run down of the parts I've ordered:
  • Prusa i3 (box) small hardware kit (no 608ZZ, cable ties or bulldog clips)
  • 10 LM8UUs
  • GT2 belts & pulleys
  • Prusa i3 (box) smooth rods
  • Prusa i3 (box) threaded rods
  • Prusa i3 (box) wood
  • Plastic parts for Prusa i3 (box) excluding extruder
Hopefully all the parts will be delivered shortly and I can get to work building.

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