25mm mirror mounts and Pro head install

[geartech]

I just about have my new mirror mounts for 25mm mirrors and new pro style head with 25mm mirror and 20mm lens installed on my K40
When I get done with it tomorrow I'll post the pics of the new brackets I made for it.
They are a little bit of a shoe-horn to make them fit but it looks good so far.

This was good practice for when I build my 900x600 table and frame. Plus all the parts will transfer over
the the new build.
Thanks for all the cool parts Marco.

[geartech]

Here are the finished photos, New mirror mounts for 25mm Si mirrors, 25mm pro head with 20mm lens.

The new brackets took some time to sort out. Would have gone faster but I didn't have a metal break to do my
bending. And doing it by hand with a vise is hit and miss, sometimes the bend is just a little twisted and you have
to start all over.

Hint: To install the silicone lines on the laser tube, get a glass HOT water with a few drops of dish washing soap in it.
Put the end of the hose in the hot water and allow it to soften. The little bit of soap will lubricate the hose and when it dries it
acts like glue. The nice thing about the soap is it wont attack the hose like some lubricants and it locks it on the fitting.

Looks like I may have an extra z table as the new head has an adjustable length.
Now on to collecting parts to build my 900mmx600mm unit.

[lapoltba]

I wanted the adjustable head for my k40, but I was told that it was too heavy for the puny steppers to move reliably. My understanding is that the added mass may cause the machine to "loose steps" and throw off alignment. Have you had a chance to test yours yet?

I really want to buy one of these heads instead of the crap one that came on my k40. Is there any reason you used the 25mm over the 20mm head? I cant imagine there is any benefit on this machine, just added cost of the head, mirrors and lens. Can you use a 38.1mm lens with this or the adapter that Light Object sells?

[weeb]

Wow, really nice looking job there. Respect m8, that's taken it past where I have gone.
Seeing it can be done, damn you, lol, I gotta try that.

[geartech]

To add that head I had to make a new mount out of 16 gauge steel so it wouldn't flex.
As for the steppers I've upgraded my stepper drivers and added a AW708C and if need be I've got a set of stronger motors.
It's mostly used for cutting and at those speeds I haven't run into any problems.
I'll do some engraving this weekend to see if there are any problems but I'm not
foreseeing any issues.

[Tech_Marco]

One thing that I'm concerning is the tiny belt could wore out quick after adding so much mass on the machine. It is not just motor alone.

The max speed that a K40 can run without escaping (losing steps) is about 450mm/s. Some may argue that they can get 500mm/s or 550mm/s. But the true is that reading or the LCD or on the setting doesn't mean anything. Remember that the laser head need time and distance to accelerate and to decelerate. That said, the laser head may need to slow down before it reach 500m/s because of limited size (340x220). On your configuration, I think (actually I guess), you may reach 300mm/s without escaping. You need to engrave a square box say 50mm * 50mm see if it come out straight (90 degree at each angle). If not, you need to slow it down.

Anyway, I can't wait to see it in action. Show us some video if you can


Marco

[lapoltba]

Can't wait for some test results. I really want one of these. Even if it isn't good for a stock K40 I'm not too concerned as I plan to use a smoothieboard and higher torque stepper motors. That may also require better belts but that also isn't an issue.

Fabricating a mounting bracket is the easy part.

Is there any way to use a 38mm lens with this head? Do any of the lens holdwrs/adapters fit it?

[geartech]

Not sure about the 38mm lens, but there should be no reason the 38mm focal length lens wouldn't work.
My head uses a 25mm mirror and 20mm focus lens. They have a 20m x38mm focus lens here on LO so it shouldn't be a problem.
The 63mm lens is about as long as you can use, due to the depth of the bed of the k40. I ended up making 2 different tables for it
One is a frame with vertical alum bars for cutting and a flat plate with adj feet to level the bed. Focal length is now taken care with the head.
The great thing about the mirror mounts is they are much easier to align. Took about 5 min to realign after putting it back together.

[lapoltba]

I did mean 38mm FL lens, not diameter, sorry for the confusion. I assume the 20mm dia lens would fit, but the nozzle would be too long wouldn't it? You would need a shorter nozzle/lens holder i think.

[geartech]

I'm pretty sure you can get shorter nozzles, If you are just enraving with the 38 you wouldn't need the air assist nozzle.