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Feb 24, 2015, 08:01 AM
HJG
HJG
HENRY
TStanley01,
I obtained my aluminium from here https://www.aluminiumwarehouse.co.uk.
I used 2" X 1" x 1/4" "C" section aluminium for the frame, the "2" side became the side and the dual 1" sides formed the top @ bottom.
The lamina aluminium strips were 1.5 " inch deep by 1/16" thick I needed 36 of these at a nominal 1" centre spacing. These spanned front to back of the laser bed i.e. shortest distance.
I also had to notch these by 1/4 " so that the strips were on the same level (at the face side) as the top of the aluminium frame. Wooden spacers (72) were fitted into the frame ( front and back sides) and the strips epoxy'ed in .
The frame was assembled on and old drawing board with corner mdf jig pieces to hold it together with laser side of bed face down .
Please be aware that this is quite a time consuming job and requires accurate cutting of component parts, the cost of the aluminium alone came to 129-33
but I had no choice as I required a custom solution.
You will need as a minimum, a metal cutting bandsaw a sliding mitre saw with metal blade or access to these items. I made the overall length and width of the bed 5.0 mm shorter than the fume box which it sits in.
As regards strength of the aluminium it seems ok in vertical loads for this span size
but I would not want to slide loads across it. It will be o/k for distributed loads such as Balsa sheet, plywood ect If you needed to span a greater shortest distance then you would probably need to consider a midpoint steel bar running
through the centres of all the lamina strips.
Regards
Henry
Last edited by HJG; Feb 24, 2015 at 08:08 AM.
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Feb 24, 2015, 09:25 PM
Registered User
Yea that does sound time consuming and I don't have a band saw. It's hard to find a table for a 4X6 co2 cutter that isn't $1000. Forget making it move. Cause the price goes through the roof then!
Feb 25, 2015, 04:45 AM
AndyKunz's Avatar
Thread OP
Get Marco's frame. It's worth it.

Andy
Feb 25, 2015, 09:18 AM
Registered User
He doesn't make one for my table.
Feb 25, 2015, 11:31 AM
AndyKunz's Avatar
Thread OP
I thought you had the same 900x600 as me.

Andy
Feb 25, 2015, 01:19 PM
Registered User
1800x1200
Feb 25, 2015, 04:57 PM
HJG
HJG
HENRY
TStanley01,
I have struggled to get my beam alignment on my 900 x600 correct, very fiddly and time consuming with inter related adjustments.
Good luck with a 2X version, slightly off topic does your wife know how to change a car tyre?, if not show her this video
http://www.flixxy.com/mid-air-airplane-repair.htm
Feb 25, 2015, 07:28 PM
Registered User
Yea, it was a pain. But just get your combiner and laser parallel, then adjust the tube up till it matches the red dot. Then go from there. Its all about being parallel. Don't worry about the beam being in the middle of the mirror. Cause if the beam doesn't move the whole way it travels then you can't adjust the mirror to make it fit to the mirror, you have to move the mirror. Good luck though. It took me about two days with a friend. Then I moved it back 3 inches and then had to re-do it.
Feb 25, 2015, 07:41 PM
Registered User
I forgot to mention that you have to adjust the laser tube up evenly.(Equal turns each end) Cause if you adjust the front or back more than each other, then you knock it back out of parallel. Also, you need to get the physical height of the first mirror in line with the second, because although you can loosen the housing and adjust its left and right movement, its up and down is fixed once you re-tighten the bolts.

So adjust the 1st stationary mirror so that it is vertically inline with the second one attached to the gantry. Then adjust your beam combiner and/or tube to the same height. From there you start the process of aligning the red dot to the laser.

There was more to it, and it's hard to explain in text, but once I understood the proper steps, it went really quick. I could probably do it again in an hour.
Feb 26, 2015, 05:32 AM
HJG
HJG
HENRY
TStanley,
I did not fit a combiner on mine, I did the following:
using Corel draw printed out loads of templates ( 3 different types)
1 type for first and 2nd mirror
2nd type for moving head
3rd type for going on bed.
these were glued onto card and then cut apart when dry
the laser tube was made parallel to back of X-Y frame, next the corner/ 1st mirror was set it matched the centre of laser tube spacing (y axis) and spaced in x axis to match 2nd mirror distance away from frame.
Next I made a little manual control box and a longish lead to control the laser power and operation, this was wired to gnd , +5v , in (pwm), and ttl "L" connections on laser power supply after isolating the existing "in" & "l" connections from the awc608.
I donned my laser safety glasses and with some blue tack attached carboard target
on 1 st mirror frame, pressed fire switch blimey! instant flames.
turned pot to correct setting replaced target and repeat and adjusted as necessary ad- nausem .
finally got to last target on laser bed and fitted focus lens using very short bursts
with lowest power setting aligned last mirror to cross hairs on target.
line target up by removing nozzle tip and lowering tube to target shift as necessary then retract tube then fire beam,, Simple!!, Not
Must make some more targets if I have to do this again at a latter date.

Henry
Last edited by HJG; Feb 26, 2015 at 05:41 AM.
Feb 26, 2015, 04:25 PM
Registered User
Yea, I couldn't imagine doing this without a visible dot. The control box is a great idea. Having to walk 15 feet around this giant gantry after every firing was a pain.

Andy,

Are you going to need that tap again? If so just let me know!
Feb 26, 2015, 04:32 PM
AndyKunz's Avatar
Thread OP
Probably will. Just waiting on my friend to place the order.

Andy
Feb 26, 2015, 05:34 PM
Registered User
Finally got my switches is. They are a nice size and I can push them with my pointer finger, so I think it is a win. Got 5 of them for about 35 bucks!

PS. Ignore Harper, she is examining my screwdriver and Fluke meter so she can help Daddy with his toys!
Feb 27, 2015, 04:52 AM
HJG
HJG
HENRY
Hi,
Well , had a setback yesterday my so called bargain Stanley compressor from Screwfix which is incredibly noisy in operation went legs up.
What are you boys using for air assist and does it run reasonably quietly? Also
the airbleed valve that fits on the laser head does not shut off the flow when screwed fully in .I have ordered another inline air valve that has push fit connexions and will mount this on X axis beam.
I will put the dust cover over the machine whilst this part arrives and work on providing a small bench/ table to locate PC and Monitor.
Feb 27, 2015, 09:30 AM
AndyKunz's Avatar
Thread OP
I have my air valve fully open all the time. I have a separate switch on my control panel for it.

The pump I'm using is overkill. It's in the BOM in post #1 of this thread. It's not too noisy, and I have ideas to reduce noise but right now I'm having too much fun cutting

A lot of back pressure causes noise, as does not having a filter on the intake. It surprised me how much quieter the pump runs with the air intake system I put on it vs. disconnected.

Instead of using the needle valve at the head, if I felt I needed to have variable flow I would look instead at a bleed valve closer to the pump, exhausting excess air.

Andy
Feb 27, 2015, 12:38 PM
Registered User
My needle doesn't shut off the flow either. I use the 24v actuator that Marco sells. I've got my needle all the way open and have my regulator set to 20 psi running pressure. The filter is a pressed floss that is I believe 1 micron, with a water and oil drain. It takes about 10 minutes before the tank drains enough for the compressor to kick on and it runs for about 60-90 seconds. But that compressor is way too large for just this. Please ignore how horrible my walls look. I probably should have painted my garage before moving this thing into place.
Feb 27, 2015, 02:48 PM
HJG
HJG
HENRY
Hi,
Well that's some setup there TStanley, I don't have room for such a fantastic
compressor like that. Andy I looked twice through your B.O.M. but did not see any air pump/ compressor mentioned.
So is 20 psi about right for air assist, and flow rate required per min would be??
TStanley do you power your air actuator from the dual 24v and 36v power supply and do you operate it directly from the awc608 or does it require some sort of interface?
Henry
Last edited by HJG; Feb 27, 2015 at 02:54 PM.
Feb 27, 2015, 03:04 PM
AndyKunz's Avatar
Thread OP
WOW! You're right, I'll have to update that tonight.

This is the one I bought: http://www.ebay.com/itm/Elemental-O2...item3f42d599e5

This is the intake filter I use with it: http://www.ebay.com/itm/ONE-Pneumati...item2c6856fc2a

Andy
Feb 27, 2015, 03:46 PM
HJG
HJG
HENRY
Hi Andy,
Thanks for the reply, my mate Michael is gong to bring round his compressor tomorrow and we will see how that fares.

Henry
Feb 27, 2015, 04:25 PM
Registered User
Yea, I already had it or I'd never consider something like that. It gave me an excuse to finally run air lines to the front of my garage.

Yes, It can be wired directly to the DSP, but I've got mine on a switch. I'll probably move it over to the DSP though. I can't think of a situation where I would want to run the air assist when the gantry isn't working.
Feb 27, 2015, 11:02 PM
Neophyte hacker
portablevcb's Avatar
I have run cheap Harbor Freight airbrush compressors. They last about two years of heavy use.

Next I had planned on the aquarium pump. I use one of those is our water system. It runs 24/7 and has been in use for 2 years so far. That's the kind of use they are made for.
Feb 27, 2015, 11:51 PM
Registered User
So I just realized after playing with these switches that although they will handle different voltages, you have to wire the LEDs in series with the load powering the device on your switch. So if I want the LEDs in the switch to turn on and off with the switch, I have to run the entire switch on 12 volt and use a relay to power all of my 5v and 24v systems. It's starting to turn into a pain to use these switches.
Feb 28, 2015, 12:16 AM
AndyKunz's Avatar
Thread OP
No, that cat has two easy ways to be skinned!

If you put a large resistor in the LED+ line, you can still use the LED and let it be powered by the AC. The downside of that is that you have both the hot and return leads attached to the switch (although there is a large resistor between them).

The other thing you can do is use floating, isolated 12V power. Then you connect the negative of the floating 12V to the one side of the switch and the 12V to the LED side, and it glows when powered.

Yes, it's more expensive, but it does the job.

Andy
Feb 28, 2015, 01:01 AM
Registered User
Cool, yea I was a little annoyed a minute ago. But I looked and even if I want to go with the expensive relays with the heat sinks it was only 25 bucks. Plus I have a $25 credit with Marco cause he reduced the price of his DSP a few weeks after I bought mine, so he gave me and a few others a credit. Not sure what I'm going to do yet. I think by the time I get the little 12v power supplies, I probably would be within 10 bucks of the relays.
Feb 28, 2015, 09:55 AM
AndyKunz's Avatar
Thread OP
The relays are a safer, easier-to-understand operation.

Andy
Mar 02, 2015, 03:05 PM
Registered User
What CFM is your air vent. I was looking at small 4" inline vents and they are 100-150 cfm. That doesn't seem enough.
Mar 02, 2015, 03:27 PM
AndyKunz's Avatar
Thread OP
Quote:
Originally Posted by TStanley01
What CFM is your air vent. I was looking at small 4" inline vents and they are 100-150 cfm. That doesn't seem enough.
I use my Craftsman Dust Collector 21335 for the air. I can't find ratings for it specifically, but similar ones are 650 cfm. I'm comparing it to the W1735 Dust Collector for size/power/etc.

Andy
Mar 02, 2015, 11:05 PM
Neophyte hacker
portablevcb's Avatar
The vent size depends in part to how much bed size there is. My little laser (12x24) used a 4" duct. The 24x36 uses 6" and 2hp blower.

The amount of 'smoke' produced is the same. The larger 'flow' is mainly used to keep a good vacuum on the table for holding down the wood.

charlie
Mar 02, 2015, 11:28 PM
Registered User
Mine is 1800mm X 1200mm. Sounds like mine might have to run off of a diesel engine.
Mar 03, 2015, 05:47 AM
HJG
HJG
HENRY
TStanley,
Why not take the approach Andy uses, simply block off the bulk of the bed you
are not using, just leaving a reasonable amount of unblocked area around your work piece.
By doing this you can use a more reasonable sized extraction system and save energy/ money.Even cardboard may suffice as the blocking medium.

Henry


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