I’m about to print a bracket that holds two adjustable laser diodes (and a vac hose holder + swivable protection shield) and I was thinking about two cross line lasers which I plan to get aligned just in the center of the cutting laser AND THEN the two crosses will meet in the exact hight (when properly adjusted) - right?
I could do so also with two spot laser Diodes, but crosses seem to be better visible, what do you think?
Especially when I want to custom home the laser on an already cut hole or inside a structure on the material or on the precise 0,0-edge, which is maybe never gonna happen, but I’m considering this just in case.
Ah…dunno. I’m unexperienced until now so I don’t know how much precision is necessary. I think a few 1/10 mm won’t hurt much.
A cylinder or rod seems to be precise and I can fall back to this any time, but as I’m designing that bracket anyway this idea popped up. The current dot laser seems useless to me for aiming or z aligning.
Afaik it’s advisable to place the focus in the middle of the material to spread the beam spreading evenly? Or is that overengineering?
So I’m thinking to align z with the laser cross and then “move a bit upwards”…I might install a caliper later for that if that method proofs to be good. Or install the bought stepper instead of the DC z motor and then use the z stepping…I’ll see. That’s secondary.
This is a known “trick” to manage cutting through thicker materials. But normally we focus at the material top, then drop it down only if needed for materials thicker than normal.
Focus is at the top of the material due to the methods used when seting the focus.
I’ve created something along that line, no pun intended. It uses a pair of line lasers, straight line, not cross. In so doing and placing the laser ninety degrees apart, they will always cross at the burn point, regardless of nozzle height. I tend to bump things a bit, which means that I have to adjust them periodically.
In taking these images moments ago, I discovered that the left line laser is weak and may need to be replaced.
I will typically focus the nozzle, pop off a pulse burn in a convenient location and set the cross point of the two lines. Once set, they will cross at the dot regardless of height.
The 3D print files are available on request in OpenSCAD format for easy modification on request, if one tends to such things.
Yeah, that’s roughly how it’s gonna look like. I have added a tube bow for smoke extraction, although the most smoke will be under the table. But at least for engraving it is important.
And to protect the lasers and all optics from beeing smoke covered
I’m thinking about combining a cross and a dot as this might be easier to align, will see.
It’s already on the printer, but the lasers have to be delivered.
Your adjustment is better, but prone to disadjustment with material collision or hands.
I’ll post the pics when it’s done those days. BTW: can I post videos as well? Would like to show the smoke extraction. Or do I need YT and a link?
Opinion: The laser diodes will not maintain their position / alignment on a holder under the random stress of the vacuum hose and shield.
The cross-hatch lens tends to have poorer resolution than the simple lens for a dot. In addition, judging a precise junction where four lines meet is much harder than overlaying two dots.
I will see…I think a cross and a dot will befine bc it covers all I need. I’ll start with two crosses and report.
The bracket ist quite strong, I will fix the laser diodes with glue once I have the focus correctly. the hose is an extreme flexible silicone spiral hose, I’ll show you.
But the fixation will be very unusual bc I dump that stupid lid of the machine and come from above with the hose, instead I rely on the little shield and I will cover the broad beams with a sheet metal cover.
It’s all a lot of hassle, but in the end I hope to have a nice workflow for all metarials and operations with no odour in the shop.
Thanks, will do that as soon as I have something worth to show.
Link for hose:
It’s in German, sorry, but it might help you to search it. Maybe AI or a searchmachine translates this.
I have the 25mm version which should be ok for the tiny amount of smoke.
It bends a bit oddly, not very smooth (like PU hoses do) in kind of 50mm sections when unguided, but due to the silicone material it withstands lots of tight bends. It would be possible to use it inside an energy chain.
And…it’s fireproof. We had a 152mm hose attached to a 50kW wood oven in a large workshop for fresh air intake. I soldered a flange to a plate and close to that was a silicone seam for some reason. It once overheated and had a flame backdraft, the soldered connection snapped, not the silicone stuff. Hose was completely unharmed.
I plan to let it dangle free from above the appr. center of the workspace, last attachment appr. 50cm above the table. With some slack and a springy holding arm (3mm round steel) this seems to work fine as first freehanded test have shown.
Seems to work fine, but I need to solve some problems:
the nozzle does not tolerate any torque and is easily turned loose. First, I tightened the upper brass “pipe” which is a part of the carrier, not the nozzle. Then it is necessary to strongly tighten the hand nut.
I had to manually modify the bracket as you see to get access for pliers to turn the laser diodes. Next version will have a spring and an adjustment screw. Diode fixation is ok, but unsatisfying.
I need to find my exact focus before I can present some real results
the z motor is a bit too fast, or it’s too fast regarding the movement of the two crosses. I had some back and forth before it looked fairly good.
which means to me: if THIS z speed oughts to be good, the crosses definetely are sufficient for focusing
fun fact: two of the crosses always show the laser center, the other two move with z, so there’s not too much crisscrosszigzagging and new centering: the laser is easy to point on a specific coordinate/mark/custom 0-0
the laser diodes are focusable, which ist perfect, the lines are rezor sharp. BUT the focus head has so much play it destroys all precision. Need to stabilize that…with glue (permanently…not good) or shrink tube.
smoke extraction video will follow (other thread), the 25mm hose sits loosely in a 40mm hose (bc I want to use 80% of the vac power for my vac table down hold, suction seems very high and silent
