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FA-MAS mostly metal delta build - AKA Metal Gear

Posted by FA-MAS 
Re: FA-MAS mostly metal delta build - AKA Metal Gear
November 27, 2017 11:42AM
Checked the lower triangle
It's constructed so that all the towers are placed equally apart, within 0.2 mm
I'm pretty sure the upper triangle is built with the same accuracy (I'll double check when I get home)
I could shim these to get them super close, but I don't know how much of an effect that would have

I also checked that the bed is perpendicular to the towers
Also that I'm using metal corners, I'm fairly sure they're rotated at all

I'm confident that all 6 rods are the exact same (I use the same jig for all 6, 1 at a time. Though I don't know the exact length center to center)
I'm also fairly confident the bearings on the carriages are the same level
Also there's no play in any of the rod ends or the linear rails

***

The only thing I'm really not confident in is that the spacing between the bearings on the carriages, and the effector
They are different. I did shim them with the smallest washers that I had to get them close, but I believe they're still 0.3 mm difference.
I'm planning on shimming or filing to get them more accurate.

***

I also have a question,

It's possible to move the carriages one at a time correct?

What I'd like to do is move them all to a measurable position. Say I have a rod or something (measuring stick) I can place against one of the lower triangle vertices along one of the towers. Move that carriage to barely touch the top of that rod. Do the same for the other 2. Set that position as a known X0 Y0 and a Z height of my choosing. But then I'd know the exact center of the bed. Would there be a way for me to measure endstop corrections from there?

Edit: Guess I could do it the hard way. Adjust an endstop correction one at a time using M666, re-home, place my measuring stick and then move the whole effector down. Then do the same for the other 2?

Edited 2 time(s). Last edit at 11/27/2017 12:30PM by FA-MAS.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
November 27, 2017 01:14PM
If you are running RepRapFirmware then you can use G91 followed by G1 S2 commands to move the carriages individually. See [duet3d.com].

You could also generate a height map using M557 and G29, and publish it here. Some height map patterns are indicative of particular issues.

Edited 1 time(s). Last edit at 11/27/2017 01:16PM by dc42.


Delta printer calibration calculator, mini IR Z probe, and colour touch screen control panel: [escher3d.com]

Large delta printer, and other 3D printer blog postings: [miscsolutions.wordpress.com]

Disclosure: I have a financial interest in sales of the Panel Due, Mini IR height sensor, and Duet WiFi/Duet Ethernet [www.duet3d.com].
Re: FA-MAS mostly metal delta build - AKA Metal Gear
November 28, 2017 12:13PM
Took about 2 hours and went over the entire machine yesterday.

Adjusted the lower triangle so precisely that it put the towers within 0.01 mm difference

Placed the bed directly on the triangle

Double checked that the towers were perpendicular to the bed using a big square, I did have to adjust one slightly

Adjusted the upper triangle so precisely that it put the towers within 0.01 mm difference too, this one took a little doing. Even though I had my extusions milled by misumi, one of them was slightly longer and wouldn't allow me to adjust the distance to what the others are. I had to file it down.

Top and bottom frames triangles match

Now the effector/carriages

I knew they were different, by 0.5 mm
I though shipping them with a washer that I thought was 0.5 mm would work. I found that the washer was 1.0 mm
I removed them and ended up filing down the effector/carriages to get them to within 0.02

Put it all back together and tweaked my config.g file slightly
Homed, ran G32 S2 and got this

************************
9:03:45 AM
G32 S2
Calibrated 6 factors using 10 points, deviation before 0.401 after 0.006
************************

Before I couldn't get it sub 0.014

I haven't tried a print yet, but soon.

Edit: Forgot, I found a loose pulley. I don't know if I just never tightened it up or if it had worked itself loose. Fixed that too.

Edited 2 time(s). Last edit at 11/28/2017 07:29PM by FA-MAS.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
November 28, 2017 12:35PM
Excellent result. If you probe just the central 100mm or so, of the bed you might see an even lower number.

But that's about as good as its likely to get without searching for the hairs in the palms of your hands.


Simon.

[www.precisionpiezo.co.uk] Accurate, repeatable, versatile z-probe plus piezo discs, endstop cables, pt100, 50w heaters. PT1000 cartridge sensors plug straight into duet boards and others.
Published:Inventions
Re: FA-MAS mostly metal delta build - AKA Metal Gear
November 28, 2017 12:39PM
That's actually a 150 mm diameter probing area.

If I set it to probe 212 mm diameter, it goes to about 0.013 standard deviation. I was more just testing probing edge to edge, I'd probably not print out that far though.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 11:11AM
Still having a problem getting that first layer perfect enough. It's either too high or too low in parts. Here's a heightmap.

also here's the probe section of config.g

M558 P1 X0 Y0 Z0 H5 F900 T3600 ; Set Z probe type to unmodulated, the axes for which it is used and the probe + travel speeds
G31 P500 X20.5 Y-12.5 Z3.376 ; Set Z probe trigger value, offset and trigger height
M557 R75 S20 ; Define mesh grid

And my bed.g

; bed.g
; called to perform automatic delta calibration via G32
;
; generated by RepRapFirmware Configuration Tool on Fri Nov 10 2017 13:27:35 GMT-0800 (PST)

; Clear any bed transform
M561

; Probe the bed at 6 peripheral and 3 halfway points, and perform 6-factor auto compensation
; Before running this, you should have set up your Z-probe trigger height to suit your build, in the G31 command in config.g.
G30 P0 X0 Y74.9 H0 Z-99999
G30 P1 X64.87 Y37.45 H0 Z-99999
G30 P2 X64.87 Y-37.45 H0 Z-99999
G30 P3 X0 Y-74.9 H0 Z-99999
G30 P4 X-64.87 Y-37.45 H0 Z-99999
G30 P5 X-64.87 Y37.45 H0 Z-99999
G30 P6 X0 Y37.4 H0 Z-99999
G30 P7 X32.39 Y-18.7 H0 Z-99999
G30 P8 X-32.39 Y-18.7 H0 Z-99999
G30 P9 X0 Y0 H0 Z-99999 S6
Attachments:
open | download - heightmap.csv (595 bytes)
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 11:43AM
Judging from your Z probe trigger height, you are not using a nozzle contact Z probe, so I guess you have a Z probe that is offset from the nozzle. In which case, any geometrical error that causes the tilt of the effector to vary with XY position (i.e. most types of geometrical error) will cause the trigger height to vary with XY position, giving you a false height map. See [duet3d.com].

What type of Z probe is it, and how far from the nozzle is it?


Delta printer calibration calculator, mini IR Z probe, and colour touch screen control panel: [escher3d.com]

Large delta printer, and other 3D printer blog postings: [miscsolutions.wordpress.com]

Disclosure: I have a financial interest in sales of the Panel Due, Mini IR height sensor, and Duet WiFi/Duet Ethernet [www.duet3d.com].
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 11:45AM
It's one of your ir probes. it's offset X20.5 Y-12.5
As far as Z, the edge of the board is 1.5 mm away from the bed when the nozzle is touching
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 11:56AM
Judging from your height map, I think you have some variable effector tilt as the effector moves in the X direction. I suggest you put a circular spirit level on the effector so that you can see what tilt there is; and/or measure the height of the bottom edge of the sensor board above the bed at different positions.

You can compensate for varying trigger height in bed.g using the H parameter on the G30 commands; but G29 bed probing will still be affected by variations in trigger height. So you may be better results if you don't use mesh bed compensation, just auto calibration.

Can't you get the sensor closer to the nozzle? When I was using an IR probe on my delta, I had the back of the sensor about 11mm from the nozzle, making the offset of the sensitive area about 13mm. Here's a rather old photo of it.



The later version used the new style E3D heater block, the new style IR sensor, and a silicone sick over the block.


Delta printer calibration calculator, mini IR Z probe, and colour touch screen control panel: [escher3d.com]

Large delta printer, and other 3D printer blog postings: [miscsolutions.wordpress.com]

Disclosure: I have a financial interest in sales of the Panel Due, Mini IR height sensor, and Duet WiFi/Duet Ethernet [www.duet3d.com].

Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 12:00PM
How do I adjust the trigger height at each point?

It's looking like a G30 at each point, and adjust the H parameter for the difference between the trigger height I have in G31?
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 01:51PM
Here's what my initial trigger height at 0,0
3.534

Here's my bed.g and where it triggered at each point,
I just include the difference, plus or minus in the H parameter correct?

G30 P0 X0 Y74.9 H0 Z-99999 - 3.650
G30 P1 X64.87 Y37.45 H0 Z-99999 - 3.676
G30 P2 X64.87 Y-37.45 H0 Z-99999 - 3.568
G30 P3 X0 Y-74.9 H0 Z-99999 - 3.791
G30 P4 X-64.87 Y-37.45 H0 Z-99999 - 3.798
G30 P5 X-64.87 Y37.45 H0 Z-99999 - 3.771
G30 P6 X0 Y37.4 H0 Z-99999 - 3.621
G30 P7 X32.39 Y-18.7 H0 Z-99999 - 3.551
G30 P8 X-32.39 Y-18.7 H0 Z-99999 - 3.711
G30 P9 X0 Y0 H0 Z-99999 S6
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 02:07PM
I've done G32 with those adjusted probe trigger heights, and started a print. The first layer looks alot better. Except, It's like the bed is tilted, so one corner of a square (100 mm x 100 mm) is squashed too much. I had to babystep it to get it to print clean. There's got to be some way of adjusting for that.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 03, 2017 02:51PM
Blah, I think I may have figured it out.

So 2 things,

When I adjusted the frame to be geometrically perfect, to ensure the towers were at 90 degrees to the bed, I placed the aluminum plate on the lower triangle and measured it that way. Problem is, I later placed the bed on printed holders to mount it. Turns out they varied slightly in height, probably introducing a tilt. I did away with those and the print bed is directly on the triangle now, held down by some M4 screws.

Second, back when I had installed the ir sensor, and it didn't seem to be triggering reliably. I got a replacement, but never installed it because the original all of a sudden started to trigger reliably. Well, it stopped again. I replaced it and it's been fine. I found that there was in fact a solder joint that wasn't soldered on the original one as the ir reciever fell off when i barely touched it.

Printing another first layer,
Thus far it looks good possibly could use some fine tuning on the Z0 position, but it looks promising.

Edit: ohmygosh, I forgot to tension the belts from when I adjusted the frame.

Edited 1 time(s). Last edit at 12/03/2017 03:08PM by FA-MAS.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 04, 2017 12:15PM
Anyone want to buy an aluminum delta frame. I think I'm going a different direction. 800mm towers, 355mm horizontals.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
December 10, 2017 06:28PM
Frame's for sale if anyone wants it.

http://forums.reprap.org/read.php?94,800287

Edited 1 time(s). Last edit at 12/10/2017 06:28PM by FA-MAS.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
May 01, 2018 09:07PM
I'm sorry to see the frame isn't working as it should, but I think you're giving up too fast.

The arms look a bit too long in my opinion. It gives me the feeling I want to write holding the pen close to the eraser.
If I were you I would check all arms between them to see if they are equal. Just stand them all up against the table and see how even they are now. They also have to point in the same directions.

This guy is using 10/7mm rods, and it seems he knows what he's doing. Select 1.25X speed and watch the whole thing:
[youtu.be]
He has too long videos, but you should see what he did with those strong arms. They worked just fine, but he made a new design just because he could:
[youtu.be]

Also, lose the IGUS, and buy proper carriages that you don't have to drill holes yourself. Get used to the thought they suck, and move on.
[forums.reprap.org]

I'm surprised you didn't check the aluminum extruders between them-self before you installed them. Too bad you paid for them to be cut "professionally".
Now it's a bit too late, but I would have? also checked the famous Robotdigg corners between themselves, stacked on top of each other, and than checked the angles.
Build, or better yet buy a good (long enough) 60° template and a 90° one, and check all angles.

Make sure the bed is actually straight, cold and hot, and don't just use your eyes to check. Take thermal expansion into account. If those M4 hold the plate too tight, something's got to give.
Also make sure both sides are parallel to each other.

As others said before me, carefully read this [duet3d.dozuki.com] . I'm sure you overlooked something.
"Unfortunately, auto calibration can't easily distinguish between bed tilt and differences in tower separation."

You have such a beautiful setup. It would be a shame to let this baby die. You seem smarter than me, based on CAD and what not. Show yourself you can finish this build.
If you sell, someone else is going to build a good delta and you'll regret selling it.
No need to reply to this if your mind is set on selling.

Edited 1 time(s). Last edit at 05/01/2018 09:10PM by Gheorghe.
Re: FA-MAS mostly metal delta build - AKA Metal Gear
May 01, 2018 09:18PM
I’d have continued troubleshooting it, but it really did come out larger than Inthiught would. I really won’t have room for it at this size. I’m now closer to a makerspace, I might shrink it down and try again.
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