J-Frame Buildlog

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J-Frame Buildlog

Postby pjeran » Sun Dec 09, 2012 3:07 am

The tots are asleep (for now) so I figured I would get a start on my build log.

First a couple of thanks:
Bart - for setting up the excellent virtual space for talking about these things
LightObject/Marco - a valuable resource for the DIY laser community and very responsive to his customers
Liberty4Ever - For the kick to start my own project

After buying/building/using several CNC set-ups, I have developed a motto that if you are going to go for it, go as large as you can. Generally you can always do the smaller projects on the larger machines, but not the other way around. I know there are exceptions to this rule, but most days of the week you can't beat a large working envelope. To this end, my plans are to use a custom modified XLE X-Y stage from LightObject to provide a working envelope of 900x600 (this is now a standard configuration), a 80W Reci laser and the DSP to control it w/ a 2.X type structure and skins. This was about as large as I could go in my shop and still be able to walk around.

I have a Mitsumi order in for the structure right now. I beefed up to 25mm square extrusion, both for strength and for a $2/m lower cost :-)

The stage is very nice, it will greatly reduce the time on alignment and getting everything running smoothly. Mine made the journey from China directly, it was well packed and went together with minimal trouble.

The Box.jpg
The Box


Lots o packing.jpg
Lots of Packing


Included in the package were lots of extra bolts and the hex wrenches needed for assembly. After assembly, measuring corner to corner there is less than .5mm difference. To get the X aligned I pulled out some 1-2-3 blocks to make sure that the left and the right sides of the X slide were in alignment.

Adjusting for eveness.jpg
Left Side
Right Side.jpg
Right side
Right Side.jpg (45.32 KiB) Viewed 12614 times


I did run into one snag during the assembly of my y motor mount. It looks like they drilled the mount about 4mm off, this meant that when I had used all the adjustment for the belt tension, there was still quite a bit of slack in the system. I knocked out a quick shim to regain the ability to tension the belt and all is well. I did not even have to buy longer bolts, there were longer spares in the package of extra bolts.

Belt.jpg
loose belt not happy


The Shim.jpg
The Shim


Belt Tight.jpg
Much Better


For others looking at this set up, I would recommend it, it is stout and smooth. When designing, you can plan on the X dimension being about 10" wider than your working envelope and your Y about 5" larger. For me, it got a large portion of the mechanics finished in quick order and got me closer to an operating machine that much faster. I am guessing that there would be at least 20-30 hrs of fabrication for me to do it along with the design work and the oh S&*^!t moments. It was a good trade off for me.

I got some surplus cable guide and built some simple mounts to get it on the X & Y axis, wired up the limit switches and steppers and fired up the DSP. I used some excess shielded 4 wire mic cable and shielded limit switch wire from my CNC router, I figure where possible I will shield long runs where I can.

I am connected using the IP connection and I must say the DSP is a pleasure to use. With a little tweaking, I am getting 700mm/s travel in both directions and things sound pretty smooth. Note: The LaserCad 6.27 password is 608. I won't really be able to assess the travel quality until the laser is hooked up and I send some test raster patterns printed.

Next steps will be to build the frame and get the laser/cooling system/ventilation system ordered.

Stay tuned!

Paul
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Re: J-Frame Buildlog

Postby gavztheouch » Sun Dec 09, 2012 10:24 am

That x-y table looks great Paul, im looking forward to seeing some test cuts.
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Exaust planning

Postby pjeran » Mon Dec 10, 2012 4:17 am

Getting ready to design/order the exhaust for the laser. Lots of options. I would like to keep the sound down so that I can work at night when the tots are asleep.

Reading through things it seems that most people like to use a dust extractor designed for word working. I have one for my planer/table saw, but it is pretty loud. I know moving air causes noise, but I hope I can cut the noise down a bit. I am thinking about borrowing some technology from the hydroponics community and going with an inline blower similar to this:

http://www.amazon.com/Hydrofarm-Active-Air-inch-In-Line/dp/B002JQ14F8/ref=pd_sim_lg_1

The 6" is rated at 440CFM and the 8" is 720CFM - now this is probably at zero restriction, but still pretty respectable. My run will be very short to try to keep the ducting loss to a minimum. Right now I am thinking bigger is better and I can always put a speed control on the big one to dial it down.

Next is scrubbing the air prior to exhaust - I like the designs of the DIY scrubbers using activated charcoal and other filter media. If the scrubbing is good enough, then I won't have to worry about venting to the outside or not. I don't really want to keep the noxious fumes in the house, if I can't thoroughly scrub the air, I will clean it best I can then out the house it goes. Then I just have to deal w/ makeup air.

Again drawing from the hydroponics crowd, there are these pre-made scrubbers that look tempting. Does anyone have any experience with them?
[url]
http://www.amazon.com/LEDwholesalers-GY ... 03_02_t_lh[/url]

Any thoughts from those who have walked the path before me?

Paul
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Re: J-Frame Buildlog

Postby TLHarrell » Mon Dec 10, 2012 5:28 pm

Direct vent to outside is by far the most cost effective route to go. I'm using a 4" inline blower (designed for marine use) and 4" PVC pipe from the big box home center. I vent directly to the outside via an existing roof vent that I didn't have a problem with blocking (other nearby vent has a powered fan added). Scrubbers are costly, and they don't remove gases like carbon monoxide from the exhaust. Not everything the laser produces can be smelled. Filters and scrubbers also require maintenance and replacement filter media.
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Long over due update

Postby pjeran » Wed Feb 06, 2013 4:10 am

It has been a long time since I did an update - I am terrible at documentation so I am playing catchup.

The frame is pretty much done, I still have to finish up some small parts to finish up. I am planning skinning using Al-panel and some skinned corrugated aluminum that I picked up the local recycling center. It is a standard Misumi frame 25x25mm section with all external corners braced so that the panels can inset into the bars. There are a couple of features that are different. On the lid, it will be a dual hinge with the front folding down for access and the lid going up. For the lid, I used some torsion hinges from [url]rockler.com[/url] that will allow the lid to stay in position.

Torsion Lid.jpg
Close-up of the hinges


Framing.jpg
The frame in an early state


I am planing in the future to build a rotary attachment and don't want to deal with changing wires for the Y axis after homing the X & Y. I wired up a switch to the disable lines of all the stepper drivers and then a 4PDT on the stepper lines. One set go to the Y axis and the other to a 4 pin XLR connector inside the table area.

Switch Plate.jpg
Switch Plate


This way I can home the X & Y, hit the disable switch, move the Y to dead center over the rotary, plug in the rotary and select that stepper and enable the axis ready for action. Or at least that how it sounds in my head...

Right now I am finishing up the Z lift - I tried to do a simple one screw on either side with linear slides and had the issues with sticking. Redesign using two screws per side driven by a separate motor and a big ass belt. Waiting on the last Misumi order to complete, then I will post some pics of how that all went together.

While I am waiting on that, I am getting ready for mounting the glass. The mounts that came with the kit are nice, but I wanted to get a couple more than two points of contact on the the tube for each mount. CNC router table to the rescue - I built up some mounts that will gently hug the tube. While I was at it, I cut out some blanks with the same diameter as the glass and a hole in the center for a red pointer to get an initial alignment. Wanted to get as close as possible before firing up the 80W monster. On the other mount I have an aluminum blank with a small hole drilled so that I can get alignment between the two mounts. Hopefully this weekend the glass will be mounted up for real alignment.

Laser Align.jpg
Laser Alignment


Mount close-up.jpg
Mount Close up


I am not married to the mount set up - if anyone has better thoughts I am open to suggestions.
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