engraving quality not consistent

[Mike]

I need a bit of help, I will read the manuals shortly but thought I would ask here before spending hours trying to find out what the issue is.

I have moved my machine to a new building, first job ran perfectly on the machine, along the full length and width of travel.

Last night I tried to run three jobs and they all ended up in th bin. as the laser head/cross beam assembly moves along the length further away from the corner reflecting mirror the quaility get worse, so that it doesnt engrave all the text properly.

I am going to try cleaning the mirrors and lense this afternoon, but suspect this is more of an alignment issue. just I am not sure why the first panel ran so well?

any thoughts.

thanks

Mike

[Spooky]

Looks very much like alignment Mike, sooty mirrors won't help and cleaning them is always good but the fact it gets worse as it moves suggests to me alignment has gotten knocked in the move.

hope that helps

Best wishes

Dave

ps:If you get stuck I'll post instructions on mirror aligning (it's not hard and well worth it, as well aligned mirrors can make a HUGE difference to quality)

[Mr Bea]

Hi Dave
I am about to move my machine so I may come across the same problem. If you could post the mirror alignment instructions it may help me in the near future.

Many Thanks

[Spooky]

No prob, gimme a couple of hours to write some decent instructions up and I'll get them posted.

best wishes

Dave

[Spooky]

Aligning the mirrors on your laser is a very worthwhile bit of work. Bad alignment can cause all sorts of problems from beam scatter (cutting double lines) ,Shallow cutting (not going right through the material) ,Angled cuts (nothing worse if your cutting slots that have to fit) and reduced tube life (you have to use more power to get the job done so killing your tube earlier)
Thankfully the LS range of lasers from HPC are quite easy to align thanks to a simple design and easily accessable controls.

Before going through the exact methodology please take heed of the following, unless you are CERTAIN that your tube is out of alignment do not move it, it is very unusual for tube to go out of line. Messing with this is a sure fire way to cause problems you may need factory help to sort out or at least an onsite from Chris at HPC.

Always work from mirror two onwards, starting with your final mirror is pointless as the alignment will change as you move the others.
Firstly place a piece of thin clear acrylic in front of mirror two (2mm stuff will do) then close the cabinet.On the control you will have a button marked "Laser" simply touch this to power up the beam for a second. Release the button and open the cabinet. Take note of where the beam strikes the acrylic in relation to the circular hole the mirror is in. If it appears to be central then read down for the next mirror. If not you will find three brass screws with locknuts on the rear side of mirror one, these move the mirror angle up/down/left/right and adjust the point the beam strikes mirror two. Remember moving the mirror one way will cause the beam to deflect in the opposite direction. Only make very small fractions of turns/tweaks as over longer distances angular movements are amplified.

Once satisfied that mirror two is being struck in the centre then move a new piece of acrylic onto the face of mirror three. Close the cabinet and fire up the laser for a second. Look at your strike point and if required adjust the screws on the back of mirror two until you have a centre laser strike on mirror three.

Diverter cone / mirror three, this is the last mirror to adjust ,set the laser head 5mm above a piece of wood / acrylic, fire the beam for a second but don't remove the material. Open up the cabinet and looking from side to side see if the beam "looks" to be in the middle of the cone? If it isn't adjust the screws on the back of mirror three and test fire until it is.

If it is in the middle then set the laser to cut a 25mm square out of 4/5mm material, run the cut then remove the square taking note of the orientation. Looking at the edge of the material note if the cut is straight and perpendicular, if it is then your all finished if not then adjust the screws on the back of mirror three to compensate until it is.

Hope this is kinda clear, if not I can write it up with pictures as soon as time permits.

best wishes

Dave

[Mike]

Hi Dave

Thanks for writing this up, I managed to figure it out myself but it took an age. a small adjustment makes a big difference.

My biggest concern now is that I think I may have damaged my laser tube prior to the adjustment by “possibly” not running any water through the tube..
I have had to increase the power I need to engrave and cut by 50%, and I am sure my alignment is better than it was when I received the machine and the mirrors are all clean.

For anybody else trying the alignment here are some other points I would add.

When setting up mirror three and the laser head you have to make sure the laser is hitting the same spot on the mirror/head as the laser moves up and down the table bed.
To do this first get the laser to hit the centre of mirror three with mirror 3 located as close to mirror 2 as possible, then move mirror three to the end of table position and make sure the laser hits the same spot.
Do the same with the laser head and mirror 3..

[Spooky]

Hiya Mike,

Tube overheat due to no water supply will indeed damage the tube and / or shorten it's life.
A power requirement jump of that size suggests the tube may well be on it's way out

best wishes

Dave

[Mike]

oh well you live and learn. will have to wait until next month before I can replace it now.

Thanks

Michael

[Mike]

On another note - How much does ambient temperature affect the engraving quality? i wonder if my workshop is too cold.

[Spooky]

Hiya Mike,

It doesn't really unless your cooling water is getting hotter than usual due to ambient temps.

best wishes

Dave