Prusa i3 3D printer

[tekkydave]

New Ramps board just arrived

 

[Gina]

Ah yes, I see.  I haven't yet found any ABS that's odour free when printing though it does seem to vary from one batch to another.  Some has hardly any smell and some stinks - don't know why there should be any difference.  Have to say most of it isn't too bad.  But having said that I shall be making a stink cupboard for my Pilot - the Titan is already in an enclosure which forms the frame.

[tekkydave]

Moved all the Pololu drivers from the old to the new Ramps board and fitted it in the case.

I also added an extra driver in the E1 position to implement the dual z-axis driving. I made the mods to Marlin and uploaded it but it wasn't very successful. The motor plugged into the E1 driver seemed to be changing direction randomly. I have put the previous version of Marlin back while I investigate further.

[tekkydave]

Fitted a different Pololu driver into the E1 position this morning and tried again. It seems to be working now so must be a duff driver. I have adjusted the pots on both and can now get up to 300mm/s on the z-axis whereas I only used to get 198 maximum. It may go faster but I'm not going to push it as the z-axis doesn't need to be super-fast. I have set the following max feedrates in the Marlin Configuration.h

#define DEFAULT_MAX_FEEDRATE          {150, 150, 4.3, 25}

So the z-axis is now 4.3 (258mm/s) - it used to be 3.3 (198mm/s).

A value of 5 (300mm/s) works ok but the motor noise is at a pitch that goes straight through you (and annoys the wife & cats) so I have backed it off a bit  . Also the two z-axis drivers now only just get warm whereas the single one driving 2 motors used to get too hot to touch if driving for more than a few seconds.

This is a really simple upgrade for anyone with a spare E1 slot. Just pop in a Pololu and uncomment the following line in the Marlin Configuration_adv.h file

//#define Z_DUAL_STEPPER_DRIVERS

then just move one of the z-axis motors to the E1 motor pins and that's it.

 

[tekkydave]

I could also implement dual z endstops. Each z motor has its own endstop and homes independently. It ensures the x axis is always parallel to the frame and doesn't drift out over time due to missed steps by one of the z motors. I would need to allocate the ABL probe to a spare pin on the Ramps as it is currently using the z-min endstop connection and doubling up as the (single) z endstop.

[Gina]

I tried my Pilot printer without any fan cooling for the stepper drivers and they didn't get warm so I think the fan is probably overkill but I'd prefer to be safe.  The fan goes back to the days of timing belt drive and maybe even screw driven Z.  Regarding my Titan printer, I gave it a quick go yesterday and it didn't print well at all but ATM I'm concentrating on my imaging rig.  I don't want to be caught out with another clear night and not be ready to image!!  Weather forecasts are pretty useless.

[tekkydave]

The M3 threaded inserts and thumbwheels arrived so I have inserted them into the ends of the two halves of the case shell.

I drilled out the holes to 3.5mm first as the inserts are 5mm dia. It is best to put a long M3 screw into the insert before heating with a soldering iron and pushing it into the plastic. It ensures it goes in straight and no molten plastic oozes back up the centre and blocks the thread. With all 8 inserts done the case can be assembled and held together with the thumbscrews.

I then reattached the case to the printer frame with the front half removed to allow the wires to be re-plugged.

After plugging all the cables back in and connecting up the PSU I printed a 20mm test cube.

It came out within 0.02mm in all dimensions so pretty pleased

The small pcb hanging off the LHS is temporary until I get the temperature controlled extruder fan working. It consists of a 5v to 12v step-up converter which runs the fan from the 5VSB so it is always on. It was in the old control box behind the RPi but will be redundant at some point. I need to build a Mosfet circuit to control the fan from a spare pin on the Ramps Servo connector.

[Gina]

My goodness that's posh   Lovely job   My stuff is more practical than pretty but yours are both

[tekkydave]

Thank you

[iapa]

On 13/12/2014 at 17:03, Dave_D said:

looks good.... now, if only cnc routers would drop in price like 3d printers have...

now you are talking

your own dovetails and other adapters.... oh... yes!!!!

[iapa]

On 21/09/2015 at 18:55, tekkydave said:

The promised piccies.

This is the first failed print of the sensor bracket. I removed the curves and holes and tried again

Can the plastic from failed prints be reused at all?

[Gina]

I did look into the possibility of building a "recycle-bot" but there are a lot of difficulties - the need to chop the plastic into small enough pieces to feed into a hopper that in turn feeds an Archimedian screw and forces the bits into a heating tube and thence through a nozzle of appropriate size.  I calculated that the power used to heat the filament and force it through the nozzle would actually be more than the cost of new filament, it's so cheap these days.

There are proprietary "recycle-bot" machines but they cost more than most 3D printers - also some DIY machines can be found by Googling but you would need pretty good engineering skills to make one.

[tekkydave]

Yes, I thought about building one until I saw how complex it is. It's not really worth it unless you have a lot to recycle. I can imagine a prototyping shop or educational establishment might benefit but not the average 'tinkerer' like me.

[Gina]

I have several dustbin bags full of scrap filament!!   I guess I might be the most prolific creator of scrap filament on SGL!  Unfortunately a recycle-bot can't be made with 3D printed components for the most part   I'd love to make one but I think I have better uses for my time.  If someone came up with a viable way of chopping up 3D prints I might reconsider it.  I hate waste - I bet I've spent hundreds of pounds on filament in the last few years

[Gina]

This has caught my imagination again   I really HATE all that scrap ABS and this is a nice difficult project - I like a good challenge as you know   Anyway, now it's reared its ugly head how can I refuse the challenge!!  But it will have to fit in with some of my other projects.  Yes, I'm afraid this project has my name written on it!

Recyclebot

[Stub Mandrel]

I'm watching this with interest, I hope to get a Prusa kit soon. Any pointers on what to avoid and what to go for? Cheap is important ;-)

[iapa]

On ‎13‎/‎12‎/‎2014 at 17:03, Dave_D said:

looks good.... now, if only cnc routers would drop in price like 3d printers have...

I suppose £1K isn't too bad so far?

http://ooznest.co.uk/3D-Printer-CNC-Kits-Bundles/OX-CNC-Machine

 

[Dr_Ju_ju]

If your looking for a kit, the current 'Internet' favourite is the new'ish Original Prusa i3 MK2 (http://shop.prusa3d.com/en/3d-printers/59-original-prusa-i3-mk2-kit.html), being so popular, it has a long lead time....

I have one & it handles everything I throw at it.....

[Gina]

That new Prusa is very interesting   Not cheap but full of great features such as the automatic calibration feature.  Now that is really novel   I have to do that calibration manually by printing a square and then adjusting.  The automatic system needs a special print bed and that will be costly.  I have not (yet) seen such a print bed with combined heater and calibration points available for those who want to build from scratch - I can't match that!  I wonder if there's another way - something to think about

[Gina]

Oh my!...  Here I go again - more project work!   Some sort of automatic (or aided) calibration for not only X and Y axes but also skewing.  My Pilot printer needs the frame mechanically adjusting for skew, Titan has guitar tuning keys for that purpose.  Z/Y/Z calibration adjustment involves editing and re-uploading the Marlin firmware.  I'll stow the thought at the back of my mind for the moment and something may emerge later

[Dr_Ju_ju]

Well, I was in two minds to point you in that direction......

The MK42 bed, is a suitably etched PCB, with a PEI sheet covering (they can be bought ), so if you can etch large PCB, its not beyond realms to make your own. & all the parts (STL's) are on GitHub...

[Gina]

That's fine   But no, I won't be etching my own PCB.  I like the bed heaters I've already got - just two or three minutes to go from 20C to 100C.

[tekkydave]

4 hours ago, Dr_Ju_ju said:

If your looking for a kit, the current 'Internet' favourite is the new'ish Original Prusa i3 MK2 (http://shop.prusa3d.com/en/3d-printers/59-original-prusa-i3-mk2-kit.html), being so popular, it has a long lead time....

I have one & it handles everything I throw at it.....

I would recommend the kit I bought but the supplier has now quit the market. The Original kit is a bit overpriced for a self-build. I would be looking to spend about £350 max for a kit. Also it depends on your skills. If you are ok with electronics, soldering, updating firmware etc then get something basic and improve it yourself.

[Gina]

I bought an expensive kit thinking it was better than the others but in most ways it wasn't.  Mind you that was a few years ago and things have advanced enormously since then so I guess I can't really advise on modern printer kits.  But I would agree with Dave that if you are good with your hands and understand how things work and feel up to it, a cheap kit that you can use as a basis for a DIY printer would be the way to go.

[Stub Mandrel]

My thought was to get a 'base model' I3 off the bay, then pimp it up as I go along. Are the ~£170 ones complete kits or do they need a lot of extras?