help needed to align laser beam

[maria galligan]

Hi I have a 40 watt k40 laser engraver which i just got new reflective lenses for and I need help aligning the beam on. Tried but when I set the second mirror when it is closest to beam to the middle but when I move it far away the beam has now moved off the mirror and its holder altogether to the left. Even though it was in the middle to start with.

So how or which is the best way of setting the beam. It has only two mirrors then the laser head. Is there any good videos I can watch? :confused:

Thanks Maria

[Dan Hintz]

It's a mirror, not a reflective lens (no such thing). If the mirror is mobile and the beam location changes as the mirror is moved, the beam needs adjustment. If the location moves up/down, the tube needs to have one of the ends raised lowered until the beam is horizontal. If the beam moves left/right on the mirror, one of the tube ends needs to be shifted left/right. Only adjust for one direction at a time, else it's like hitting a moving target. These adjustments can also be made in similar fashion to the first steering mirror (the non-moveable one).

[maria galligan]

I had a quick look at the machine today and it looks like there's no movement in the laser tube. This machine has no name on it but it looks exactly like a Shenhui K40 laser engraver. Ill have to do some modifications too allow some tube movements. Does it really matter which end of the tube moves?
Thanks Maria

[Mike Null]

I have zero experience with Chinese built lasers but I'd at least check the mirrors first to see what kind of adjustment is possible before tampering with the tube.

[Richard Rumancik]

What brands of lasers have tubes that require aiming? I thought that all the laser systems had fixed tubes and all the alignment was always done after the tube, although I have not seen how a glass tube mounts. I suppose that it is possible that there is more toleance in a glass tube mounting system. But I agree with Mike; I'd want to be certain that I needed to do this before I drilled out holes (or whatever) to make the tube "adjustable". There are quite a few points of adjustment already and adding another adjustment might make the puzzle even more complex. I'm not saying adjusting the tube axis can't fix the problem, but I'd make sure that there isn't another way . . .

[Dan Hintz]

Richard,

The bigger Chinese systems usually come with adjustable tube mounts these days (one did it and the rest copied the design, of course). Sometimes the mirrors don't have enough adjustability, so gross adjustments are done at the tube, then fine adjustments at the mirrors.

[Rodne Gold]

Shim up one side or another if the tube is held in via a V block , IE put somethen between the tube and the V block
You might need to check the the tube is like this with the mirror holders = --- and is not too low or too high like = ___ and the the mirror holders are also in the same plane with respect to each other. The k40 type lasers are not a quality constructed item , and QC is nominal at best , reflected in their price.
Do a google search on " newbie needs help with laser alignment dominic gailgan "

[maria galligan]

How do i check if the tube is not too high or low too high with mirrors? And as far as I can see the mirrors are in the same plane. But it does look like the first mirror holder is set too far faward from the tube.

[Dan Hintz]

If the tube is level, does the beam hit the center of the mirror? If not, the tube is too high or too low...

[maria galligan]

I now have the mirrors set but the beam is not being reflected down through the engraver head. What would cause this too happen? And how do I fix this?

[maria galligan]

I can now set all the mirrors and get the beam going through the laser head when I press the test button but when I output from moshidraw the beam is not being reflected through the head. What's going on here?

[Dan Hintz]

If it works with the test button but not with Moshi, the obvious answer is Moshi is probably not properly enabling the laser.

[maria galligan]

I now see the mirrors are being damaged. They being burnt, and one broke inside the mount. They were brand new mirrors from Shenhui lasers. Please look at photos. Why did this happen? How do I stop it?:confused::confused:

[Rodne Gold]

Is there a plastic covering on the mirrors? Are they blue or is that a reflection ? As I said before , that is a really entry level machine and it sells for a price where everything is compromised , ask Shenhui if they have better mirrors for you ($22 each). There is a chap that is modifying one of the machines like yours on the board that comes up if you do my google search , he might have info for you.
The post is "modifying a cheap laser" or something like that.

[Ernie Balch]

the rabbitusa website has a nice procedure for aligning a laser system. The photos will help a great deal for the first time doing alignment.

[Dan Hintz]

When you're aligning this thing, you should only need to press the test button for a second or two to mark the paper and see where it lines up. It looks like your burning through the paper and getting soot on the mirrors and lenses, which will destroy them in short order. When you get new lenses and mirrors in, go through the alignment process before doing anything else.

[maria galligan]

Hi
To answer some of the questions. The mirrors are orange, not blue and that is not a reflection but a burn mark.What Dan said is what,s happening. It's soot from burning the paper. I didn't know that was no good to burn the paper on the mirror. A hard lesson learnt, will know for next time. I have the last 2 new mirrors and will try again today set set it. I know what was happening yesterday. It was the soot mark stopping the beam. Ill look at rabbit usa site as well as the cheap laser modification. Thanks for all the advice it helps us newbie's.

[Rodne Gold]

Yellow/Orange optics are generally lenses - Mirrors are either gold or silver..and VERY shiny, did you mean gold not orange?? if you have soot marks on the mirrors , you should be able to clean them quite easily , no need to use "new" ones.

[maria galligan]

Yes they are gold not orange. But how do I clean the soot of the mirrors?

Thanks Dom

[Dan Hintz]

Yes they are gold not orange. But how do I clean the soot of the mirrors?
Lots of threads to answer these basic questions... I'll suggest again, start at thread one and start reading, there's way too much useful info to pass it up. Start with some reagent-grade alcohol, or in a pinch, just use some isopropyl alcohol.

Thanks Dom
You've signed off as Dom on several occasions... who is Dom?

[maria galligan]

Hi thanks. Dom is Maria's husband. We are both trying find out information together because we are trying to start a small business personalising products. So we need to get our laser working. That's why there's been so many questions. But thanks to you all and the help you are so willing to give we are slowly learning.

Thanks Dom and Maria

[Andrzej Piechota]

Hello Maria
Please read this link: http://www.rabbitlaserusa.com/Manuals/BeamAlignment.html . This is description of setting mirriors and lens for correct beam from tube to engraved material.
brgds

sorry not see that this was already posted

[Larry Robinson]

One thought is to make sure you start your mirror alignment with the mirror closest to the tube and then work your way toward to the head mirror. This should be explained in the manual. A LOT of patient is required to do the mirrors the first time.

[maria galligan]

The problem I have is that when I set the laser head mirror the beam moves a lot. When I set it closest to the second mirror it's fine but when I move the laser head to the far position the beam moves 40mm to the front of the machine. But both mirrors are set in the middle. I have noticed that the second mirror and the laser head are not lined up. I mean the laser head is 7mm closer to the tube on the gantry than the mirror is. Is this a problem? There is no more adjustment faward on the laser head nor is there any front to back adjustment on the mirror bracket? Any help please?

Thanks Maria

[Dan Hintz]

Pictures would help significantly here.

1) The gantry should be parallel with the top/bottom edges of the table... if it's not, fix that first.
2) Then, the tube should be (ideally) parallel to the table (though it's not a necessity). If you can't adjust this, don't worry about it, it's not critical and can be fixed with the first mirror adjustment.
3) Both the tube and table should be perfectly horizontal (or at a bare minimum, parallel to each other in the horizontal direction)... if they're not, fix that next. This is also not critical and can also be fixed with the first mirror adjustment.

Once that is done, start adjusting the mirrors in the following order:
4) Beam should hit the first (non-movable) steering mirror dead on the center.
5) Beam should hit the second (movable) steering mirror (attached to the gantry) dead center at the top of the table and at the bottom. If it doesn't, adjust the first mirror to make it so.
6) Beam should hit the third (movable) steering mirror (on the carriage) dead center at the far left and far right of the table. If it doesn't, adjust the second mirror to make it so.
7) Beam should hit the focusing lens dead center. If it doesn't, adjust the third mirror to make it so.
8) Go back through steps 4-7 and make sure nothing has significantly changed position.

[maria galligan]

Thanks Dan

Ill have a look at this in the morning and ill post some photos then also.

Thanks Maria

[maria galligan]

Here are some pictures of this problem. The one photo shows how the mirror and head are not parallel. I don't know if this is a problem?

[Dan Hintz]

Focus, please!

That first image, if I'm viewing it correctly, shows a major problem... if the second mirror (the one on top) is not in line with the third mirror (on the carriage), you have no hope of keeping the beam centered when the carriage moves. Resolve that issue before doing anything else.

[maria galligan]

How do I know when the second mirror and the laser head mirror are in line? The second mirror bracket is home made so it could be that the mirror was put on the machine in the wrong place. Should I use a visible laser light to check beam path?

[Mike Null]

Dan

I would think that the alignment has to begin at the tube. I don't know of a way to align the mirrors with each other unless the tube is aligned with the first mirror.

Again, I have no experience with this machine but it seems fundamental that all adjustments must begin at the tube and mirror no. 1.

Homemade mirror bracket?????? Why?

[Dan Hintz]

How do I know when the second mirror and the laser head mirror are in line? The second mirror bracket is home made so it could be that the mirror was put on the machine in the wrong place. Should I use a visible laser light to check beam path?
Why are you using a homemade bracket? What was wrong with the one that was in the machine? From the image you posted, the offset that bracket creates will never allow the beam to be aligned... the bracket either needs to be removed or re-engineered. Use a handheld laser pointer if you must, but it's irrelevant... I can look right at it and tell you aligning that system with the current position of those mirrors is impossible.

I would think that the alignment has to begin at the tube. I don't know of a way to align the mirrors with each other unless the tube is aligned with the first mirror.
As long as the first mirror (the one that doesn't move) can be adjusted in both X and Y axes, the laser tube itself could be in the next room. Ideally you want the tube to be parallel and level to the table, but it's not necessary by any means as you can tweak out any amount of skew with the first mirror. Once the beam travels past that first mirror, however, the beam must be parallel and level to the table (as it travels down the side of the table to bounce off of the second mirror attached to the gantry rail)... if it's not, the beam will eventually get off-center as the second and/or third mirror travels farther away.

[Mike Null]

Dan

I'm saying that the tube (beam) must be aligned with the first mirror to begin the process.

[maria galligan]

I didn't make the bracket the chinese made the bracket. It's just some bent up aluminium. If you have a look at the pictures on the previous page it's there. Which bracket are you talking about Dan. The second mirror bracket? I thought that bracket was very poor when the machine arrived. Very poor chinese work. Should I buy new brackets for this machine? What about the mirror mounts are they ok? What do I need to do with the existing bracket to make it work?

[Dan Hintz]

221448 Notice the red line is parallel to the gantry rail and goes through the center of the carriage (third) mirror. Now notice how the line does not go through the center of the gantry (second) mirror at the top of the pic? The second mirror has to either shift to the left, or the third mirror has to shift to the right. If you try to steer the beam using the second mirror in its current position (blue beam), the moment the carriage moves the beam will no longer be hitting the carriage mirror.

[maria galligan]

Thanks Dan ill have a look at that today and see what I come up with.

[maria galligan]

To get the beam set I had to reset the tube as it was not set right and then had to move the laser head a lot to set the beam. So thanks to you all for your help.

Maria

[Jim West Jr]

If this is still an issue it sounds like the laser tube isn't firing under Moshi control. Check and make sure your laser enable switch on the front panel is turned on.

[Dan Hintz]

If this is still an issue it sounds like the laser tube isn't firing under Moshi control. Check and make sure your laser enable switch on the front panel is turned on.

Considering this thread is over two years old, I imagine the OP got his situation resolved... or he has tossed the machine in the trash in frustration.

[Matt McCoy]

This might help:

http://m.youtube.com/watch?v=RjhvEfKQ_Mo