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View Full Version : How to straighten a machine twisted during shipping



Eric Ucci
03-09-2012, 3:05 PM
Caveman style!
Well I purchased 2 machines from Shenhui. One came twisted due to damage from shipping. The insurance claim has been filed and I was told that I could attempt a fix. Precision tools used in this procedure include...

Auto pump jack
shore posts
clamps
railroad tie

Actually, it appears as though we've returned it to dead straight again! LOL226586226587

Mark Sipes
03-09-2012, 3:31 PM
Ugh ! ( who ships with the wheels on? ) Every pallets needs a smaller, ill fitting pallet under it.




With the volume of sales this company is making...they should hire an install team to follow up and improve shipping/missing item issues....setting the system up (software/traing) sounds like a plus also.

Mike Null
03-09-2012, 4:10 PM
Those are pretty sophisticated tools. Surprised you didn't have a sledge hammer.

Bill Cunningham
03-09-2012, 8:28 PM
Those are pretty sophisticated tools. Surprised you didn't have a sledge hammer.

It's not called a sledgehammer Mike.. In this precision business you adjust it to a fine thou with your 'Knockometer' ;)

Randy Digby
03-09-2012, 11:27 PM
Good job Eric. Reminds me of long, long ago when we actually drew engineering drawings on paper with pencils (you can Google pencils) using triangles, drafting machines, French curves, engineer scales and other obsolete tools. On structural designs we would often put in the notes section: BTFPTM and wait for the shop to call for an explanation: Beat To Fit - Paint To Match.

George M. Perzel
03-10-2012, 7:33 AM
Randy;
You bring up memories, you forgot slide rules and having to do drawings in ink using those damn ink pens that worked on capillary action and always dropped a blob of ink when the drawing was almost finished-I hated that damn course in engineering school and still have nightmares about it.
Best Regards,
George
Laserarts

Randy Digby
03-10-2012, 10:26 AM
Funny you should mention inking drawings. I had just dropped one little drop of ink on my drawing and was waiting for it to dry to remove it with a razor blade when the instructor looked over my shoulder and announced to the class, "Mr. Digby, I believe you could take one drop of ink and paint this entire classroom!" Memories.

Frank Corker
03-10-2012, 4:28 PM
Eric, looks like the same sort of stuff that I have seen mechanics use to get an insurance 'write off' back on the road. Most of the laser is just box anyway, I'm sure you'll get it right. It's what the machine can do which is more important than the outer package. I can remember some really ugly people at work, but they could work really well anyway :)

Richard Rumancik
03-10-2012, 6:02 PM
Eric - did the insurance company reimburse you for your effort? Have you been able to fire it up yet? You really need to look close for any other less-obvious damage.

Eric Ucci
03-10-2012, 6:40 PM
Richard,
No, I have not been reimbursed yet. Although I am supposed to be reimbursed for the repair costs. I expect to have it fired up in a few days and be able to judge if there is additional damage. I have often been told I'm too impatient. But, I made the judgment that I could fix it myself and be done with it rather than deal with the weeks/months that it will take to deal with insurance. Plus, I was told that if I do experience problems due to that damage, I will be covered since it has been photo documented and a claim has been filed. You are correct that there may be less obvious damage. Especially considering the forces required to bend one of these machines. I'm no expert, but I'm fairly confident that the rest of the machine isn't damaged. Besides, I like a challenge. I wouldn't have bought these machines if I didn't. :)

Rich Harman
03-10-2012, 9:57 PM
I think the most import thing to look for is that the two Y axis rails are in the same plane.

Eric Ucci
03-10-2012, 10:40 PM
Rich,
This was also my main consideration. Once i noticed that the machine was racked, this is what I was eyeballing to crank the machine back to straight. Now they are co-planer. And with a very accurate square, the gantry is perpendicular as well.

Richard Rumancik
03-11-2012, 2:33 PM
Yes, the y-rails need to be in the same plane but also that plane needs to be parallel to the table. If you haven't done so I would suggest clamping a dial indicator to the carriage and moving it around the table to check that the engraving plane follows the plane of the table. If you don't have a dial indicator handy then a stiff piece of wire or pointer clamped to the carriage along with a set of feeler gages will give you an idea of how parallel the two planes are. If it is out of parallel, you may have to shim the y-axis rails to get it fine-tuned. Or tweak the table, or both . . . depending on the numbers and type of twist that you see.

Eric Ucci
03-12-2012, 12:36 AM
Rich R.,
This sounds like a useful exercise with both machines. Judging from the flatstock which connects the table to the acme screw threads (and the fact that they are not level on either machine) I'm guessing that there will be plenty of delta at all corners in any machine from the factory.
This also brings up another issue. Assuming that I do get all 4 corners set to identical height, the way that the honeycomb table is made, the best i can hope for is level at the perimeter, with a sag toward the middle. The honeycomb table in captured in a u-channel frame that is roughly .02" thick. If I take this honeycomb table and place it on a perfectly level surface, It will still sag in the middle by the gauge thickness of the u-channel. I was considering trimming that same gauge thickness at the ends of the aluminum knives so that the entire honeycomb surface can rest on the same plane. This sounds a bit persnickety, but if the goal is the kind of precision that you are describing, it may be time well spent now, before we're off and running.

Richard Rumancik
03-12-2012, 12:43 PM
It really depends on what you are making as to how parallel you need to be and how much sag of the honeycomb table is tolerable. If you normally use long FL lenses they will have more depth of field and are more forgiving. But in my opinion there are enough other errors and problems to deal with that I tend to fix the things of which I have control as best as practicable. There are plenty of things you can't control easily - such as beam divergence - so it may be worth the effort to level right from the beginning.

Would it be possible to just add a few support shims under the honeycomb rather than trying to modify it? These could be bonded, but I'd probably just set a few shims on the main table below the honeycomb as needed (if I understand your explanation correctly.) I'd be hesitant to rework the honeycomb.

Rich Harman
03-12-2012, 4:07 PM
You can loosen the z axis belt then move each jack screw individually to adjust the table height. Loosen only enough to turn the jack screw with a wrench so that it can skip teeth on the belt.