[Lab] laser mirror holders

krazatchu . krazatchu at hotmail.com
Thu Nov 4 14:55:42 EDT 2010

Mirrors are not perfectly efficient... 
At 100w, even small inefficiencies will be significant... 
Poor dissipation of even half a watt of heat can cause some serious localized heating...

At higher powers, the laser mirrors are water cooled.... 
I have no idea of exact numbers however, nor what search terms would reveal...


From: darcy at siteware.com
Date: Thu, 4 Nov 2010 14:44:52 -0400
To: themumbys at gmail.com
CC: lab at artengine.ca; ORE_bits at yahoogroups.com
Subject: Re: [Lab] laser mirror holders

pretty well an inch. They say they are 1" or 25mm. Pretty thin. Like a mm or so.
I don't think it heats .

On Thu, Nov 4, 2010 at 2:43 PM, Paul & Andrea Mumby <themumbys at gmail.com> wrote:

exactly 1" circle? 
Also what is the approximate thickness of the mirror?
And to your knowledge does the mirror heat up during use (and if so to what approximate max temperature)? I would assume they are designed to fully reflect the wavelength your laser operates at, but if they heat beyond a certain point we need to consider the thermal stress on the printed parts, since the thermoplastic used in 3d printing softens at a fairly low temperature (both PLA and ABS) I would need to compensate for that in the design.

- Paul

On Thu, Nov 4, 2010 at 2:00 PM, Darcy Whyte <darcy at siteware.com> wrote:

It should be easy to drill and tap into a cupcake part if needed. If you have a better idea, cool....

The mirror is a 1" circle.

On Thu, Nov 4, 2010 at 1:58 PM, Paul & Andrea Mumby <themumbys at gmail.com> wrote:

I assumed it didn't need to be the same as the ebay one, but that gives me an idea of the mechanics, so I know what type of behavior I'm emulating... 
I'm not sure about the threaded hole idea, but I'm sure I can get something equally as effective from a printed part for sure.

If you can bring the existing one that would give me another hands-on example, and I could take some pics of it too to use for reference... is the mirror itself circular? or square?

I'll let you know shortly if we can meet tonight.
- Paul
On Thu, Nov 4, 2010 at 1:27 PM, Darcy Whyte <darcy at siteware.com> wrote:

The mirror holder on my cutting head has a 1" threaded hole. you slip the mirror into the hole and there is a threaded circle that you screw in to pinch it down into the hole.

If we are able to meet tonight I'll bring that one. 

It doesn't have to work the same as the one on ebay. As long as it can hold the 1" mirror and be tilted for adjustment (through a screw or something to make it accurate).

On Thu, Nov 4, 2010 at 1:23 PM, Paul & Andrea Mumby <themumbys at gmail.com> wrote:

Ok, so if I get the mechanics from those photos, their particular design has the flat square bracket (with the circular hole) which would be the plate which the mirror itself would be fixed against. This pivots on a ballbearing in the corner of the L shaped bracket, with 2 center springs under tension, which keeps the corner set screws under compression, allowing you to adjust the X and Y tilt, the L shaped bracket has 2 holes one in each "arm" which I'm assuming are for mounting the whole apparatus to your machine...

I'm not sure how the mirror is affixed to the flat plate with the circular hole, they mention plastic tipped screws, but I don't see that anywhere in the pic, but I might be missing that... Either way if my above assumptions of the mechanics are correct, I should be able to mock up a design for this quite easily... 

If you have any other input to offer that might let me get something mocked up in time to show you tonight.
I'll confirm with my wife when I get home from work if tonight is ok for a quick meeting, and if she's ok with that then I'll email you and confirm timing and such early this evening...

Does that work for you?
- Paul
On Thu, Nov 4, 2010 at 12:44 PM, Darcy Whyte <darcy at siteware.com> wrote:

Did you follow the ebay link I sent?
Okay, we can meet up tonight later if you want. Just send me the address at time to darcy at siteware.com. I can probably come around 9 or just before 10 for a quick meeting.

On Thu, Nov 4, 2010 at 12:41 PM, Paul & Andrea Mumby <themumbys at gmail.com> wrote:

I'm in Bayshore... My house and workshop are a bit of a disaster area lately though lol... I think my wife would shoot me if I invited someone in right now :)
Either way, we could meet quickly to discuss your options, if you have some hand sketches or something of the parts, and bring along some samples, and dimensions, I could mock something up tonight/tomorrow, and we could discuss it more at the faire... your right in that there might not be a ton of time, but I was surprised how easily the design/testing cycle works now that I have rapid prototyping capability... Small parts take 20min to print or less, so I can easily whip up a design in an hour or less, print it, and take an iterative design approach to something that is normally much more monolithic... It wastes a bit more material, but since material costs are so low for the plastic filament, it's totally worth the agility gained in the design process...

Let me know what your thoughts are and we can talk about it. 
I'm a bit busy tonight and tomorrow, as I also have some paperwork to catch up on for my home business, and some other todo items to deal with (I've been multitasking between print and other stuff) but I could probably afford an hour or so either tonight or tomorrow between 8pm and 10pm to discuss options. Otherwise we can talk at the faire and meet up sometime following that if that works better.

Even an email with some sketches/dimensions and pics of parts and so on might let me mock up something quickly if that's preferable as well.

- Paul
On Thu, Nov 4, 2010 at 12:26 PM, Darcy Whyte <darcy at siteware.com> wrote:

I would think that there wouldn't be much time to do it during the Maker Faire. The printing would be easy but the design (and any experiments) would take a while.
I think the plastic cost is cool. 

Where are you? If you want to try some test runs, I could drop by if you want.

On Thu, Nov 4, 2010 at 12:18 PM, Paul & Andrea Mumby <themumbys at gmail.com> wrote:

There will be several 3d printers at the maker faire, I would bet you could have mirror holders made at the maker faire with enough bartering/negotiating lol... 1" holding brackets wouldn't take long to print, it would mostly be design/testing time that would consume the most effort...

I'd be fine with printing them for you at maker faire for cost of plastic used (which would be minimal, hell I would likely do it for free depending on the volume of plastic). provided we have the time/resources to design the parts. I'm sure a lot of the other guys will have more Industrial Design experience than I do though.

Anyway, point being there will be at minimum 5 3d printers, and possibly as many as 7-8 at the maker faire. So between all of them I'm sure your parts could get done ;)
Also there is talk about kickstarting the RepRap Loaner program at the ottawa Maker Faire, so we will be trying to build a reprap mendel at the faire, and use it as a community loaner model.

I've been working on printing parts to have at the maker fair in the evenings this week (just for examples) so if you have a design in mind, or some info, perhaps I could run a few off as tests tonight or tomorrow, and bring them along, get a bit of a head start.

Let me know.
- Paul
On Thu, Nov 4, 2010 at 11:55 AM, Darcy Whyte <darcy at siteware.com> wrote:

I'm now wanting to make mirror holders. The mirrors are 1". I need two of them. They should have a tilt adjust.

Any ideas?
The artengine makerbot? What is the status of that? What is the procedure for booking it?

I'd like to try and have them done before Guy and I are finished making the mounting brackets for the laser tube.
Here are some mirror holders on ebay:


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