Niggle Build

Niggle Build

Postby Niggle » Mon Mar 03, 2014 6:13 pm

I have access to a laser cutter and a collection of Cartesian printers that are all temporarily unusable. I did gut the hub printed in ABS, but I am stalled by not being able to print the arms. So, I started by laser cutting the plates.

Rather than the nice recess that Nicholas drew, I took a Forstner bit to the holes to make a hole big enough for a 13mm socket. This left a thin wall at the edge that broke when I sanded the charred wood off the edge. The second base plate is about a 1/2" bigger all around and didn't have that problem. It also has an 8" round access hole, copying someone else's build.
WP_20140303_005[1].jpg
Standard base plate with collapsed corner
WP_20140303_005[1].jpg (1.67 MiB) Viewed 62752 times

WP_20140303_003[1].jpg
Oversize base plate
WP_20140303_003[1].jpg (1.52 MiB) Viewed 62752 times


The top plates were cut from 1/4" ply and glued together. This means that the recess for the bed heater is way too deep. So I took a piece of ceramic fiber insulation that I had lying around, cut it to fit and then teased it apart to get an 1/8th" layer to pack under the heater. I also moved the wiring hole to one of the corners, thinking that that would give me a little more structural strength and would let me keep the wiring tidier.
WP_20140303_007[1].jpg
Top plate with ceramic fiber
WP_20140303_007[1].jpg (1.52 MiB) Viewed 62752 times


I have a Mega 2560 + RAMPS 1.4 + LCD Panel, my next steps (while waiting for a printer to be repaired) will be to create mounts to attach them to the bottom of the top plate. Since I have an ATX supply to adapt and it is too big to fit between the plates, I don't have to squeeze the PS and the controller onto the plate.
Niggle
 
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Re: Niggle Build

Postby NeoTheFox » Mon Mar 03, 2014 6:45 pm

Nice start, keep it coming!
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Re: Niggle Build

Postby Niggle » Tue Apr 08, 2014 5:57 am

I finally got access to a working Makerbot2 and printed the last of the pieces (unless I break some more of them).

I also have a collection of failed prints and a shoulder that I broke trying to force the bearings into place.

Building has resumed. More pictures coming soon.

Installing the M8x60 screws into the arms was interesting. It appears that the local supply of such bolts have 22mm of thread (The M8x55 have the same length of thread). The head stands well clear of the arm (so the M8x55's would have fit) but 22mm of thread is NOT long enough for the thickness of the arm and two nyloc nuts. Replacing the inner nut with a flat nut (a perfect fit for the nut trap) left barely enough thread for a nyloc on the outside. I think that all the screws bit into the nylon but only just.

Do check your M8 screws and try to find a variety with more than 25mm of thread.
Niggle
 
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Re: Niggle Build

Postby timrwilliams » Tue Apr 08, 2014 10:46 am

There does seem to be some variation in threaded length. 25mm thread just does for 2 plain nuts and 1 plain washer. So far I have not used any nyloc nuts - waiting to see what shakes loose. After about 2 hours printing nothing has fallen off!. If anything starts to loosen I would probably go for a dab of 'ThreadLock' or perhaps some PTFE plumbers tape.
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Re: Niggle Build

Postby imrahil » Tue Apr 08, 2014 11:06 am

let's try socket cap screws - they have 28mm of thread.
like these: http://www.contakt.pl/ruba-imbusowa-8x- ... 12159.html
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Re: Niggle Build

Postby Niggle » Sun Apr 13, 2014 12:32 am

Progress
WP_20140412_001.jpg
Base
WP_20140412_001.jpg (1.33 MiB) Viewed 62555 times


Base assembled. Plastic parts kitted out.

WP_20140412_002.jpg
Controller
WP_20140412_002.jpg (1.44 MiB) Viewed 62555 times


Controller talking to Repetier Host. ATMega2560 + Ramps1.4 + reprapdiscount LCD/SD unit. PS is a scavenged 360W ATX unit.

WP_20140412_003.jpg
Spool Jig
WP_20140412_003.jpg (1.24 MiB) Viewed 62555 times

One stepper driver demonstrably working. The motor is mounted in a section of a motor arm set up so that I can send the spool round. The motor can be dismounted from the jig and mounted into a motor arm without touching the spool. I'm hoping that this will let the spool stay round.

My next steps will be to sand the spools and then string the arms.
Niggle
 
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Re: Niggle Build

Postby Nicholas Seward » Sun Apr 13, 2014 1:19 am

Clever spool rounding jig!
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Re: Niggle Build

Postby Niggle » Mon Apr 14, 2014 6:52 pm

Not clever enough :) - The current version exposes too much of the spool. When I fix that I'll post scad and stl files.

The bigger problem to get Repetier Host to spin the stepper long enough to get the job done. I don't think that I have the firmware configured correctly and I'm off to browse through all the postings to see what I've done wrong. More later.
Niggle
 
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Re: Niggle Build

Postby NeoTheFox » Tue Apr 15, 2014 7:03 pm

Niggle wrote:Not clever enough :) - The current version exposes too much of the spool. When I fix that I'll post scad and stl files.

The bigger problem to get Repetier Host to spin the stepper long enough to get the job done. I don't think that I have the firmware configured correctly and I'm off to browse through all the postings to see what I've done wrong. More later.


Try Printrun! I used to have problems of this sort woth Repetier-Host too. Printrun solved thes for me. I also made few macros buttons based on segmentize, it is really great.
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Re: Niggle Build

Postby Niggle » Sat May 03, 2014 12:54 am

It moves!

I have all the steppers connected to the controller. I have endstops mounted and the eccentric stops in roughly the right place, although I need better connectors. I have firmware downloaded.

Using Repetier Host in manual mode, I can move the X and Y arms. Asking it to move Z+ extends all three arms simultaneously. This makes me wonder about the firmware.

I'm thinking that I may have been too smart for my own good. I had told Repetier to configure the machine as a delta before I built and downloaded the firmware. Was this a mistake?

As a temporary measure, I intend to compile and download a Cartesian build so that I verify the movement of the X, Y and Z arms more or less independently. Then I will use segmentize.py to transform a calibration cube and see what the results look like.

I will certainly write up some notes about getting this to work right.

BOM comment - The BOM list qu-bd as a source for the bed heater, steppers, hotend, power supply, controller and hobbed pulley. The link needs to be updated. Using the website can be disconcerting as it does not confirm orders placed (at least it didn't when I used it). Also, the company does not have a good history of filling orders on time. However, if you get through to the support person, they can be persuaded to ship orders (I ignored them until I was blocked by the lack of a hobbed pulley. It took fours business days to get a response, but the pulley showed up two days later). My suggestion is that you consider alternate sources if you need stuff within the next month or two.
Niggle
 
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