Geeetech-Aluminum-Prusa-I3

Quote
Wildkata
New guy on the list. Retired electronics and manufacturing engineering tech.

Could someone tell me the length of the lead screws please. I'm considering buying the aluminum model and would like to order proper lead screws at the same time.

Ray

Thank you bernbout.

My printer is on order and so are my T8 lead screws. The lead screws were only $7.52 each w / shipping. I hope to bypass the z band problem from the git-go.

Should be here in a week.

I have another idea that might give acceptable results with the supplied lead screws that might even almost pass scrutiny by anonymous.

I once replaced over $70 worth of swagelock stainless fittings X 80 machines ($5600+) with a $0.06 plastic part ($4.80. + a $3.00 installation tool). The department manager (engineer + MBA) said YEAH!. The lead tech said her first impression was no way but then came around. The "we've always done it this way" crowd went ballistic. I was told by one of the techs that accepted my solution, after the three of us left those machines were quickly "repaired properly" even though none of them had failed.

Wild

Edited 1 time(s). Last edit at 05/10/2017 09:26PM by Wildkata.

Quote
Wildkata
New guy on the list. Retired electronics and manufacturing engineering tech.

1. I hope to bypass the z band problem from the git-go.
2. that might even almost pass scrutiny by anonymous
Wild

1. While using lead screws that are hopefully straight will alleviate the z banding to a high degree, IMHO it will not completely remove it. The simple reason is that all it takes is for the leadscrew (given that it is perfectly straight) to be coupled to the motor but not be perfectly perpendicular if even a fraction of a degree. off. There are other factors too that could influence z banding.

Since we are dealing in measurements as small as .01 of a mm, even a tiny deviation from the vertical will induce some form of "dancing" in the lead screws. While this may not be noticeable to the naked eye, it will certainly be more at the top end of the lead screw than at the coupler end. As the X axis rises with every layer, the deviation will be that much more. Due to the design of the Prusa i3 with the Lead screws (Z Axis) permanently "joined" to the X axis by the lead screw nuts, this "dancing" has nowhere to go but be transferred into the X axis as Z Banding in your print. The more the movement of the lead screws, the more pronounced the banding.

Also no one at home has the equipment to ensure that every thing in a DIY printer is perfectly square. Hence there is bound to be some banding. All we can do is reduce it to the max extent possible. So using straight lead screws instead of threaded rods that are more prone to bending, properly coupling it to the motor etc. will certainly reduce banding. But to reduce it even further, you MUST decouple the Z Axis from the X axis, a tried and tested method I have used and linked to earlier in this post.

2. Regarding Mr. Anonymous, he is a troll and a SAM - A Split-Arse Mechanic , similar to the idiots you alluded to in your previous post who thought they knew better. He is listed as Anonymous here because he was kicked off this forum for trolling. He even followed me on Thingiverse and tried troll me there with his crap.

Hope you have every success with your new printer.

Quote
bernbout

Quote
Wildkata
New guy on the list. Retired electronics and manufacturing engineering tech.

1. I hope to bypass the z band problem from the git-go.
Wild

Also no one at home has the equipment to ensure that every thing in a DIY printer is perfectly square. Hence there is bound to be some banding. All we can do is reduce it to the max extent possible. So using straight lead screws instead of threaded rods that are more prone to bending, properly coupling it to the motor etc. will certainly reduce banding. But to reduce it even further, you MUST decouple the Z Axis from the X axis, a tried and tested method I have used and linked to earlier in this post.

Hope you have every success with your new printer.

Again, thank you. From previous projects I have some nice tools that should help. A very true running Taig micro lathe, 12 inch vernier caliper, a set of metric thread chasers and a laser level. A dozen carbon fiber arrows with six unmolested and the other six don't shoot very well. With a left hand tap and a bag of left hand nuts on hand, four of them are going to become nifty turnbuckles to triangulate my frame if needed. I woke from my last sleep with an idea for a simple and reasonable $-wise X-Z decoupler that dare I say may be a tad more elegant than yours (if it works (it will have an anti-backlash component (Hi SAM))). I think from the wobble visible in your video, you could benefit from a little eyeball chiropractic on your screws. You might have some minor Z jitter from that much wobble. Another design I found on YouTube tonight via Thomas Sanladerer, the iTopie i3, Does not constrain the top end of the Z screws. Might have some merit, but not while your nuts are floating. [reprap.org]

Another thing I think I'll try is to get some 6>5 couplers in the same design as used and tap the 6mm end to 8mm in the lathe.

Edited 5 time(s). Last edit at 05/12/2017 05:42AM by Wildkata.

Don't forget to share your idea here if it works out.

Yes I forgot to mention squaring the vertical frame to the horizontal base. Caused me a lot of problems leveling the bed because of skewing.

That video of the "dancing" of the rods I borrowed from another guy. My rods did not dance so much and were quite straight. It was the coupler - that cylindrical springy thingi that connects the rods to the motor shaft - that induced the z banding as I could never get them both perfectly square. I printed a set of self centering couplers and that together with the de-coupler thingi fixed the z banding for me.

I have since made a number of "improvements" for my printer especially the noise of the bearings.
Checkout [www.thingiverse.com]

Quote
bernbout
Don't forget to share your idea here if it works out.

Back to the drawing board on that. Anti-backlash works different than I was envisioning.

I got the idea somewhere that you are down under but you wrote guy instead of bloke or mate?

My printer shipped from California UPS and my lead screws from Texas USPS priority yesterday, so no waiting on slow boats from China

Just slow brown land yachts.

Edited 1 time(s). Last edit at 05/13/2017 12:20AM by Wildkata.

I was from "Up above" but have lived for the last 20 years "down under". Guess old habits die hard. Have not fully adopted all the slang.
Fair dinkum mate.

Edited 1 time(s). Last edit at 05/12/2017 01:20PM by bernbout.

UPS told me they are bringing my kit by tomorrow afternoon.

Has any body tried to to file or drill a stepper motor rotor?

Generally pretty hard steel. I tried to drill a set screw hole in one of mine. Didn't work well. Tend to see a 3-point collar/hub for them in higher priced kits. The other problem is you don't really want to be torquing the living crap out of them against the axis.

Got my kit today. UPS lied to me about yesterday. Waited outside 4 hours yesterday and 2:2 today. Didn't think to check my email again before I went out yesterday. Sure enough there was an 8:04 AM notice of reschedule after the .3:31 PM notice from Sunday.

Not I'm pondering how to set up a cat proof assembly area. Don't have spare room to dedicate. My cat loves to play with my toys. His name, Enre is pronounceable two ways - the second is Ornery. I am sure he wants to be a people. I showed him how bubble wrap pops. He is so frustrated that all off his manipulators have sharp points. He brings me flat sheets and wants more whenever I get some.

Have to second the comment that you need a 3D printer to make a 3D printer. Been puttering for five years..

While researching the published problems with this kit I think I have some innovations to add to the art that I can test on this machine after I use it improve itself and then to build another..

Wild

Edited 1 time(s). Last edit at 05/17/2017 04:48AM by Wildkata.

"H ave to second the comment that you need a 3D printer to make a 3D printer. Been puttering for five years.."

nah see repstrap...

it just makes it far easier! (and yes I did it this way, but cheated on the extruder, but could have used wood)

Quote
Dust
"H ave to second the comment that you need a 3D printer to make a 3D printer. Been puttering for five years.."

nah see repstrap...

it just makes it far easier! (and yes I did it this way, but cheated on the extruder, but could have used wood)

Looks like a good resource, thank you. It's amazing what can be learned on eBay too, and YouTube. This thread has given much.

I'm surprised Prusa is not on that wiki. How much change do you have to make to justify giving it your own name?

Wild

Edited 1 time(s). Last edit at 05/17/2017 04:45AM by Wildkata.

That's just repstraps... see [reprap.org] for prusa

"How much change do you have to make to justify giving it your own name?" a significant contribution, or a really big ego!

Prusa basically designed the basic outline of most of the current machines,

Quote
Dust
That's just repstraps... see [reprap.org] for prusa

"How much change do you have to make to justify giving it your own name?" a significant contribution, or a really big ego!

Prusa basically designed the basic outline of most of the current machines,

I was surprised tonight while watching nillabean's stream just how primitive the Genuine MK2 is. I really wish they would sell their MK42 print plate so I could use their alignment test on my aluminum i3 and the designs bouncing around in my head.

the mk2 is not that primitive, lots of subtle things you have probably missed.

a) high quality parts, vs crap from china. (makes such a difference)
b) the hidden cross bracing threw the power supply mount.
c) the firmware, many features that are not available in any other firmware, ie the auto alignment tests
d) electronics and cables harnesses all just plug together, no soldering and most are locking connecters, wont fall out.
e) The bed is genius, using the inherent accuracy of PCB manufacture to embed some position markers to help with calibration and alignment.. just brilliant!

I really like the mk2, my only niggle is I wish it was a 32bit controller, preferably smothieware.
The spool mount is crap...

NB there have been (may still be) 3rd parties making mk42 boards on kiskstarter... it is opensouce...

I guess they heard you guys - mine arrived with lead screws for the Z axis. The smooth rods are not near as smooth as the G6 rods I bought. I will be miking them this evening, likely will be using the G6.

Wild

Quote
Wildkata
I guess they heard you guys - mine arrived with lead screws for the Z axis. The smooth rods are not near as smooth as the G6 rods I bought. I will be miking them this evening, likely will be using the G6.

Wild

Must have been half asleep last time I looked. Definitely plain screw rod, not lead screws. Sorry bout that. The cheaper Flsun Aluminum i3 came with lead screws. Go figiure.

Edited 1 time(s). Last edit at 05/22/2017 10:43PM by Wildkata.