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Squaring Gantry

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tylerd
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Squaring Gantry

Postby tylerd » Sat Jul 21, 2018 5:05 pm

My gantry is slightly out of square, I attempted to square it up using the info in this short video I found....https://www.youtube.com/watch?v=Gpn0p7BiuJ0. I loosened both sides and tried to adjust the it square. There really isnt much adjustment you can make due to the clearance of the bolts and the slots that the bolts go through that hold the gantry onto the uprights. The only way to adjust it any more this way would be to clearance the holes the screws go through, and would rather not have to do that! I was wondering if I could just adjust the home switch stop bolts? This would seem like a much easier method, as long as the table is pretty square which it seems to be. I have no idea if that would mess with the software settings or not. Wish there was a manual for this kind stuff! The gantry is not off by much, maybe 3/16ths or little more from on side of Y to the other, but it is noticeable. Everything else on the table pretty much kicks but, just this one little thing having issue with. Any assistance would be much appreciated!
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motoguy
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Re: Squaring Gantry

Postby motoguy » Sat Jul 21, 2018 11:18 pm

I have a 6x12, and my gantry pops out of square when the motors are powered off as well. More than yours, call it 1-1.5" (A side, in the X+ direction). It's noticeable to watch, and there's a noticable delay as the A axis takes longer to hit the auto-square switches. The X axis will hit and stop, and you get to watch the A axis continue it's way back, until it hits the switch.

That being said, other than knowing it's "sprung" a bit, it's a non-issue. The auto-squaring switches take care of it at every startup (or every time I home X if I have an eStop). Without the auto square switches, it'd be an issue.
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djreiswig
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Re: Squaring Gantry

Postby djreiswig » Sat Jul 21, 2018 11:20 pm

You should be able to adjust the homing switches so when it homed and moves off of the switches, it is square. Sometimes mine will seem to drift out of square while it is powered down. I notice it is out when I reference it the next time. It's like it gets twisted a little and squaring it makes it twist back. It was doing that again today so I loosened the gantry to carriage bolts and referenced it and then tightened everything back up. Now when I shut it off it doesn't seem to drift. I think accidentally knocking it out makes the gantry slide on the bolts a little.
I would loosen the bolts a little and adjust the switches so the gantry is square to the table and then home it a couple of times to get things aligned and then tighten them back up.
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Bigrhamr
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Re: Squaring Gantry

Postby Bigrhamr » Sun Jul 22, 2018 9:08 am

I see you guys mentioning the gantry drifts or pops out of square when you power down the motors. Is there a noise when that happens? I am just trying to get a new table set up and there is a pretty significant bang when powering off. Loosening the bolts and squaring hasn't changed it.

tcaudle
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Re: Squaring Gantry

Postby tcaudle » Sun Jul 22, 2018 12:52 pm

If the ganty is not under stress from one side not being aligned it should not do anything. (triple negative sentence) There should not be any popping or motion when motors are depowered. If it's happening with the motors still licked then something is loose. Either a gear, coupling or pulley/belt. Go to each motor and try (hard) to move it with the motors locked. ANY visible backlash is bad. Because of the torsional forces on the rotary parts simple setscrews alone may not completely lock down a part on a shaft. It it only happens when you turn off the motor DC (red button on the controller) then either one of the motors is not turning the same as the other or is simply not working and one side is doing all of the work.

djreiswig
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Re: Squaring Gantry

Postby djreiswig » Sun Jul 22, 2018 1:08 pm

Mine wouldn't do it right away. It seemed like it must have been a slow creep over time. No noises. Readjusting it like I do seems to take care of it.
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tylerd
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Re: Squaring Gantry

Postby tylerd » Sun Jul 22, 2018 2:04 pm

Awesome thanks for the responses, I will adjust the stops on the home to see if I can get it a little closer to square. And my gantry doesn't make any noises when I power off, it does not seem to be torqued or under any kind of pressure, I just think perhaps it got out of square when it was shipped, over a year ago. I know just getting around to it, day job family..etc. I do wish there was a manual for this kind of stuff but this site is great at getting a person answers pretty quick! Again thanks for all the help!
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Bigrhamr
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Re: Squaring Gantry

Postby Bigrhamr » Sun Jul 22, 2018 2:13 pm

tcaudle wrote:If the ganty is not under stress from one side not being aligned it should not do anything. (triple negative sentence) There should not be any popping or motion when motors are depowered. If it's happening with the motors still licked then something is loose. Either a gear, coupling or pulley/belt. Go to each motor and try (hard) to move it with the motors locked. ANY visible backlash is bad. Because of the torsional forces on the rotary parts simple setscrews alone may not completely lock down a part on a shaft. It it only happens when you turn off the motor DC (red button on the controller) then either one of the motors is not turning the same as the other or is simply not working and one side is doing all of the work.


Thanks, let me run something else past you.
I can do the home and auto square, jog X out a few inches and kill motor power. It will jump out of square by 3/16". Power up again and without moving it kill motor power and it goes out by another 3/16". I just repeated that 6 times with the same results making it out by 1.125" difference between the 2 sides. Any significance to that? It seems any mechanical tension would be relieved the first time, so would this be related to motors?

motoguy
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Re: Squaring Gantry

Postby motoguy » Mon Jul 23, 2018 1:49 pm

Bigrhamr wrote:I see you guys mentioning the gantry drifts or pops out of square when you power down the motors. Is there a noise when that happens? I am just trying to get a new table set up and there is a pretty significant bang when powering off. Loosening the bolts and squaring hasn't changed it.


Mine makes a small noise when powering the motors on and off. Not big, but a small "chunk" that lets you know the motors have powered up and are being held in place. Same small "chunk" when powered off.
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motoguy
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Re: Squaring Gantry

Postby motoguy » Mon Jul 23, 2018 1:51 pm

djreiswig wrote:You should be able to adjust the homing switches so when it homed and moves off of the switches, it is square. Sometimes mine will seem to drift out of square while it is powered down. I notice it is out when I reference it the next time. It's like it gets twisted a little and squaring it makes it twist back. It was doing that again today so I loosened the gantry to carriage bolts and referenced it and then tightened everything back up. Now when I shut it off it doesn't seem to drift. I think accidentally knocking it out makes the gantry slide on the bolts a little.
I would loosen the bolts a little and adjust the switches so the gantry is square to the table and then home it a couple of times to get things aligned and then tighten them back up.


Yeah, mine squares up just fine once it's touched off the home switches. I assume my gantry has a little bit of "spring" in it from something or another. It'd be a significant issue without the auto-squaring switches, but it's a non-issue with them. I've thought of loosening bolts and trying to relieve whatever spring is causing the twist, but it's not a big enough deal for me.
Bulltear 6x12 w/ Proton Z axis & watertable
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motoguy
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Re: Squaring Gantry

Postby motoguy » Mon Jul 23, 2018 1:52 pm

tcaudle wrote:If the ganty is not under stress from one side not being aligned it should not do anything. (triple negative sentence) There should not be any popping or motion when motors are depowered. If it's happening with the motors still licked then something is loose. Either a gear, coupling or pulley/belt. Go to each motor and try (hard) to move it with the motors locked. ANY visible backlash is bad. Because of the torsional forces on the rotary parts simple setscrews alone may not completely lock down a part on a shaft. It it only happens when you turn off the motor DC (red button on the controller) then either one of the motors is not turning the same as the other or is simply not working and one side is doing all of the work.


Good to know. I'll check that in the near future. Mine has done it since new (almost 3 years).
Bulltear 6x12 w/ Proton Z axis & watertable
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ggeh
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Re: Squaring Gantry

Postby ggeh » Mon Aug 06, 2018 10:28 am

I have a 2014 bulltear table that the x axis, a-axis side would jump 1-1/2" after I turned off the Dc power to the motors. I was told that the motors would not move after the power was shut off and the gantry is in bind if that happens. Matt from Bulltear said it is an easy fix. turn on your system, and auto home x-axis. With the power still on while its in the homed position remove the gantry end caps and loosen the six screws, three and each side that hold the gantry to the aluminum drive plates, two 9/16 hex head and one 1/4 allen head, then re-tighten them and replace your end caps. shut the power off to the steppers and see if the gantry still jumps.That's all there is to it to take the gantry out of bind. After this is done your gantry wont jump after your power is turned off, at leased it works on my table. I done this more than once because I leave something on the table and forget its there and then collide the gantry into it which knocks the gantry out of alignment. The motors are very powerful. Hope this helps.

Gary
Last edited by ggeh on Wed Aug 08, 2018 8:43 am, edited 2 times in total.

BTA Plasma
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Re: Squaring Gantry

Postby BTA Plasma » Mon Aug 06, 2018 11:24 am

Bigrhamr wrote:I see you guys mentioning the gantry drifts or pops out of square when you power down the motors. Is there a noise when that happens? I am just trying to get a new table set up and there is a pretty significant bang when powering off. Loosening the bolts and squaring hasn't changed it.


If you are running a Supercharged Star Lab the machine should be powered down by first powering down the large control box then the smaller one. The enable then power signals should be shut off in that order. It is not uncommon to hear a thud when powering down. The motors are very powerful both on the stepper and supercharged machines.

ggeh
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Re: Squaring Gantry

Postby ggeh » Mon Aug 06, 2018 1:55 pm

As far as squaring the table the way I do it is I use the edges of my water table with a tape measure and a sharp pencil zip tied to my torch. previously I have checked my top edges of my water table to be perfectly square, side length and diagonals. I home x and y. My water table is not bolted down so I can move it with considerable effort. I check x-0 inch to x-48 inch and make sure that measurement is the same at both ends of X-travel by adjusting the water table edge. I then check y-0 inch with y-48 inch to the other edge of my water table to be equal if they are not the same I adjust the homing switch on the y-48 side till they are. I realize there are different ways of coming to the same result but this is what works for me. I like using the edge of the water table because when I lay a piece of steel on the water bed I make the edge of the steel parallel with the edge of the water table and I then know that the steel is parallel with my x-axis travel. You can use a piece of plywood on top of your table and get the same results, I just prefer my water table edge because its square and it already there.

ggeh
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Re: Squaring Gantry

Postby ggeh » Mon Aug 06, 2018 1:58 pm

hit the quote instead of edit, sorry
Last edited by ggeh on Mon Aug 06, 2018 2:02 pm, edited 1 time in total.

ggeh
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Re: Squaring Gantry

Postby ggeh » Mon Aug 06, 2018 2:00 pm

hit the quote instead of edit twice, sorry

BTA Plasma
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Re: Squaring Gantry

Postby BTA Plasma » Mon Aug 06, 2018 2:29 pm

Gary all the machines have Auto home/Auto square switches installed. They became standard equipment quite some time ago.

ggeh
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Re: Squaring Gantry

Postby ggeh » Mon Aug 06, 2018 5:36 pm

BTA Plasma wrote:Gary all the machines have Auto home/Auto square switches installed. They became standard equipment quite some time ago.


Thanks Matt, I never stated my table or any tables didn't come with Auto home/Auto square switches installed from the factory, don't know where you got that from. I was simply stating that shop conditions some times are not perfect and things get dropped bumped or moved accidentally like a 4" pipe falling and striking my a-axis home switch screw adjuster plate that in-turn knocked my table out of square by 1/8 inch. So that's what I was explaining on how I check, and adjust the home switches if need be to bring the table back to square so when you click that x-axis home icon that your table homes to true square.

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Re: Squaring Gantry

Postby BTA Plasma » Tue Aug 07, 2018 9:48 am

Oh no problem Gary! Did your table come with the Auto Home/Auto Square switch kit installed? When are you going to stop by again? Would be great to interview you.

tylerd
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Re: Squaring Gantry

Postby tylerd » Tue Aug 07, 2018 10:43 am

Gary, thanks for the full tutorial on the entire process, the video does not mention homing the axis first IIRC. Good info to know for sure!
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Re: Squaring Gantry

Postby ggeh » Tue Aug 07, 2018 7:08 pm

BTA Plasma wrote:Oh no problem Gary! Did your table come with the Auto Home/Auto Square switch kit installed? When are you going to stop by again? Would be great to interview you.


Yes it did come with Auto Home/Auto Square, I purchased it from you and picked it up in 2014. Great table, and design, very strong. The table has taken a lot of not intended abuse from me and it still cuts like new. Thanks for a great product. Only have one regret, I should have went bigger.

Thanks for all your help Matt,
Gary
Last edited by ggeh on Wed Aug 08, 2018 8:46 am, edited 1 time in total.

ggeh
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Re: Squaring Gantry

Postby ggeh » Tue Aug 07, 2018 7:33 pm

tylerd wrote:Gary, thanks for the full tutorial on the entire process, the video does not mention homing the axis first IIRC. Good info to know for sure!



I hope it helps, I just watched the video, I forgot to include the allen head bolts on the back side of the gantry so there are three bolts on each side not two. If your gantry is in bind and you don't home your gantry first the gantry is in a relaxed position and loosening and tightening the bolts does nothing. You have to home the gantry first to put the gantry back in bind so when you loosen those bolts it relaxes/unbinds itself. If you notice with the power on to the steppers you cant move the gantry, but with the power shut off you can move the gantry fairly easily. When the gantry is in bind and you turn the power off the steppers free wheel till the gantry unbinds itself. I just put my gantry in bind last Thursday because I get ahead of my self and always in a hurry. I loaded a 48 x 48 x 5/8 sheet and forgot I still had the cherry picker hooked up and ran the gantry into it at 600ipm. Didn't break any thing but the gantry was cocked and in bind. My learning curve has been tough on this table. This forum, the information on here, and the experience the members have and the willingness to help newbies like myself is priceless and a steal for $20.00 a year.
Thanks to this site and members for your help, your great.

Gary


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