My Prusa I3 MK2 Dolly clone - Build log / progress report

Where it began and what we all love most
Stefan
Posts: 223
Joined: Thu Jun 15, 2017 12:46 am

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by Stefan » Sun Jul 01, 2018 7:30 pm

👍

User avatar
Moorviper
Posts: 232
Joined: Wed May 24, 2017 1:19 pm
Location: Hessen/Rhön - Germany
Contact:

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by Moorviper » Sun Jul 01, 2018 8:18 pm

Check cnc kitchen's vibration test if the printer is stable enough :D https://github.com/CNCKitchen/3D-Printer-Vibration

User avatar
warren.watts
Posts: 23
Joined: Wed May 02, 2018 7:18 am

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by warren.watts » Mon Jul 02, 2018 8:18 am

Moorviper wrote:
Sun Jul 01, 2018 8:18 pm
Check cnc kitchen's vibration test if the printer is stable enough :D https://github.com/CNCKitchen/3D-Printer-Vibration
I don't know if I am really THAT interested, but it's an interesting idea!

There's a great YT video that explains it all in excruciating detail as well... https://www.youtube.com/watch?v=Ws1JfHl3Y0o

Stefan
Posts: 223
Joined: Thu Jun 15, 2017 12:46 am

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by Stefan » Mon Jul 02, 2018 9:08 pm

I attached rubber to the bottom of the y-axis blocks and made sure it was as flat as possible. Biggest source of vibration on a Prusa seems to be the big pendulum on the top of the frame.

-Stefan

unixb0y
Posts: 30
Joined: Wed Apr 18, 2018 4:45 pm

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by unixb0y » Sun Jul 08, 2018 11:02 am

Hello warren,
It looks great!
I’m currently doing a MK2/3 dolly with TMC2130 and stuff.
Electronics are running, extruder is assembled but I have yet to build the frame.
It’s very hard to find a place that sells aluminium profiles with threads in the corners.
So I might instead build the MK2 frame.. ¯\_(ツ)_/¯
We’ll see once the sellers reply.
Did you cut your frame with a jigsaw?

~ Dave
~ Dave ~

unixb0y
Posts: 30
Joined: Wed Apr 18, 2018 4:45 pm

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by unixb0y » Sun Jul 08, 2018 1:06 pm

I’ve just checked AliEx.. and it looks like they’ve catched up a lot wrt MK3 since 2 months ago!
They have a full frame (3 plates plus Y carriage) for 50-70€, they have “Btech” gears for 10 bucks and also sell the MK52 heated bed!
Does anyone have experiences with these products yet?

~ Dave
~ Dave ~

User avatar
warren.watts
Posts: 23
Joined: Wed May 02, 2018 7:18 am

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by warren.watts » Mon Jul 09, 2018 4:57 pm

Did you cut your frame with a jigsaw?
Yes, frame was cut with a jigsaw, but I had a friend with a table saw help me square up the outside edges. I can't seem to cut s straight line with a jigsaw to save my life. I've been told that it may not be entirely my fault though - when you buy a cheap Black and Decker saw, you get what you pay for. I'm just not willing to invest $100 in a Bosch that I use three times a year, so I guess I have to deal with my B&D's "wandering ways"

My printer is nearly finished. The main board case is printed and attached, and the X and Y axis wired and working. Still fighting with the damn JST connector crimping tool trying to make consistent cables that work dependably. I'm slowly getting better.
The heated bed is attached, but the thermistor isn't working (I suspect it's more of my noob wiring) and the board refuses to turn on the bed without a good temp measurement from the thermistor. I forced it in the firmware just to make sure the heater does work (it does), but of course I have to have a working temp sensor. Safety is a huge concern of mine, and I am not cutting any corners.

I was hoping to get it done over the weekend, but it just didn't happen. Perhaps by the end of the week.

unixb0y
Posts: 30
Joined: Wed Apr 18, 2018 4:45 pm

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by unixb0y » Tue Jul 10, 2018 12:44 am

Hello Warren,

Thank you for your quick reply! I'm glad to hear that your printer is going to be finished soon :-)
Personally, I'm working on mine since April, so it's almost 3 months and I really want to get it finished, too.. :D I don't know if I've mentioned it, but I clone the MK3 and I found out yesterday that AliExpress now has MK3 frames, which is what I've ordered.
Going the "lazy but expensive" way 'cause I just don't have the time at the moment and having an aluminium frame isn't bad either.
Especially on the MK3 it will save me a lot of hassle that I'd have when going for wood (difference in thickness → either have to compensate with longer Y axis rods or shorter extrusions → difficult to find, risk that I'll have to buy multiple times). This way, I'll be able to get "standard" MK3-clone-Y axis rods and MK3-clone-Y axis alu extrusions.

I've had thermistor issues with my other printers in the past; don't you have some spares? They should be a few cents in Chinese shops and sure - never try to turn off those safety features in Marlin!
A few tips: You can test the thermistor with a Multimeter (measure resistance) and you can test the board with a regular resistor.

Cheers,
Dave
~ Dave ~

User avatar
warren.watts
Posts: 23
Joined: Wed May 02, 2018 7:18 am

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by warren.watts » Tue Jul 10, 2018 8:04 pm

Heated bed now working. It was indeed a bad thermistor. I am disappointed in this because the thermistor is molded into the silicone mat and is not easily replaceable. Had I had the foresight to TEST the thermistor BEFORE I peeled off the adhesive and stuck the heater to the bottom of the build surface, I would have simply embedded an external thermistor between the silicone mat and the bed and called it a day.

Since I am not about to peel it back up, now I am going to have to mount one to the bed à la Tom style https://youtu.be/jp7ubpbaw-Q

Or maybe I'll get lazy and stick it to the bed with some Kapton tape.

Sheesh. Seems like it's always something. It really makes me wonder if I shouldn't have just bought a kit and saved myself all these headaches.

unixb0y
Posts: 30
Joined: Wed Apr 18, 2018 4:45 pm

Re: My Prusa I3 MK2 Dolly clone - Build log / progress report

Post by unixb0y » Tue Jul 10, 2018 10:18 pm

Hi Warren,
Well this is how we learn!
I've spent a lot of time on modifying the MK3 extruder to work with my larger Z-Axis probe and with a MK8 drive gear instead of the new Bondtech gears and now it turns out there are P.I.N.D.A and Btech clones from China. :roll: :roll: :lol:
With regards to the bed, I don't know if the "steel sheet plus silicone heater" is the best solution in 2018.
It was the only thing available in Prusa Mendel times - sure - but today you get a nice 220x220mm bed with "integrated" heater circuit on the bottom and SMD thermistor (or sometimes just a ready drilled hole in the center) for under 10 bucks!
That's what I have on my old printer and what I initially got for the new one as well (before buying a MK42 clone - 30€).
In my past experiences, a kit will be up and running much faster (in one afternoon), but you'll be tweaking and modifying it for weeks, partly because of all of the shortcuts that the manufacturers take to save money.
~ Dave ~

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest