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Second Sourcing: Belts

December 6, 2011

So now that I have my quote in from the ULS rep for my list of parts, I thought I’d go through the list and see how much of it I can second source from other suppliers outside of the ULS umbrella. So for starters I decided to go with what is most-likely the easiest part to find elsewhere… the timing belts. Now I don’t know much about timing belts, but figured they were an off the shelf component. So after doing a little research online, I discovered that the pitch/profile for the belt is known as MXL (Miniature Extra Light). I wasn’t sure on the material of the belt, but I did come across a spec that stated it was kevlar re-enforced. After searching he usual retail suspects [McMaster Carr & SDP/SI as well as few others] it became apparent that the material must be urethane. So armed with that information, as well as the length  and width specifications for the replacement belts, I came up with some pricing:

The base spec for all the belts is: MXL (0.080) pitch timing belt x 1/4in wide, urethane belt with kevlar re-enforcing members. All are closed loop belts, for open they will be cut. (McMaster & SDP-SI don’t have kevlar re-enforced belts that are open)

Short Z belt: [meas: 105 teeth closed] (there is some flex in the length due to the adjustment mechanism, s0 103-108 should all be ok)
Primary: 105MXL, 105 teeth [8.4in] SDP/SI – A 6B16-105025 [3.52]
Alternate: 103MXL, 103 teeth [8.2in] McMaster – 1679K93 [2.55]

X Belt: [spec: 5.25ft / 63; meas: ~60in – open]
Primary: 962MXL,  [77in] McMaster – 1679K686 [9.61]
Alternate: 1500MXL,  [120in] SDP/SI – A 6B16-15C025 [21.33]

Y Belt: x2 [Spec 3.25ft / 39in; meas: ~37in – open]
Primary: 482MXL,  [38.5in] SDP/SI – A 6B16-482025 [5.54]
Alternate: 482MXL,  [38.5in]  McMaster – 1679K683 [5.84]

Now I could probably do even better here, but for 1 off, there is no real need to. At $24.21 for all the belts, I’m roughly 1/6th the quoted cost of $140! That’s $120 savings right there… if I can keep this up, I just might be able to swallow the outrageous price of the extrusion.

[yes I know the prices above are US dollars, and the quote was in Canadian, but given the value of the dollar right now, I consider them to be pretty much equal]

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The front panel (part 2)

December 2, 2011

Today I took on the front-panel control/display board. The board is pretty much charred as you can see. It has quite a few traces on it, but is fairly simple in function, thus making it relatively easy to decode.

Before even doing any cleaning I tried  to make some pretty good guesses as to the architecture, the next paragraph is my assessment from before I started.

There are 2 IC’s on it, which are likely some sort of tri-stating buffer, allowing the switch signals to be multiplexed onto a data bus. The data bus also feeds to the LCD.  Then there are the 2 LED’s, these are fairly large and probably consume a bit of current, which would explain the two transistors beneath them, likely acting as low side switches. There’s a 3rd transistor on the board, which I’m not sure of the function yet, but it should become more obvious as I trace it out.

Now lets get into it and see how well my guess did.
Read the rest of this entry »

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The front panel (part 1)

December 1, 2011

Today I took a bit of time after work to map out the membrane keypad of the control panel. Unfortunately it was badly burnt up, so unusable, and I didn’t take the best of care pulling it off.

However, fortunately enough, it mostly came off in large pieces, so I was able to put the pieces together enough to trace out the signal mapping. to make life a little easier, I took a picture from the backside where the traces can be seen, and then traced out the lines in CorelDraw. Virtually any membrane keypad can be reverse engineered this way, as they are almost always printed on transparent material. Read the rest of this entry »

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And then a step to the right

November 30, 2011

The search for replacement stepper motors is on. The first step was identifying what is there already.

Two of the 3 steppers (X & Z) are easily identifiable, as I can read the labels on them. The 3rd stepper (Y) unfortunately has had the label completely darkened from the fire to the point where all I can tell is that is is a 0.9 degree/step stepper from the one side that is still readable.  Luckily with a peek at the laser at the Hacklab, and at a picture posted by a user (lasersafe@buildlog.net) of another ULS laser rebuild, I was able to identify the make, and possibly model for the unknown stepper. It is definitely the same manufacturer / series based on what is still discernible on the label of the motor. However it is quite possibly a different model than the one that is in both the Hackalab’s laser, and lasersafe’s UL25E. (the part number, while unreadable appears to be different) Read the rest of this entry »

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Like money in the bank

November 29, 2011

I took a 5 minute break at lunch to see if I could tackle the engraving table. As this part is $500 to replace, it will be a huge savings if I can de-laminate the top sheet of aluminum off of it.

As you can see from the picture above, the top surface is badly warped. Luckily this provided good access to insert a parting tool to try and separate the top from the bottom. The hardest part of the process was actually backing out the two thumb-screws that hold the rotary attachment alignment bracket in place [seen on the left edge above]. Once I got those out, it took less than a minute to break the top panel free. The heat appears to have pretty much completely released the panel from the inner structure.

The table, as you can see above, is actually composed of a fragile aluminum honeycomb structure glued between the two thin sheets of aluminum on the top and bottom. Around the edges is a 1/2in x 1/2in solid aluminum bar to provide additional rigidity and compression strength for the mounting points. On their own, each of the components is quite flimsy [with the exception of the bar that runs the perimeter] But once glued together, it is very strong, rigid, and lightweight.

The next step, for the table, will be to give the remaining part a wash, and perhaps rubbing with some steel wool to remove all the dirt from the remaining structure. Re-gluing a couple of points on the bottom sheet, as it has come lose in a few places. And then buying and machining a new top sheet with holes in the right places, before gluing it on. Luckily I can use the bottom half of the table as a template for the machining, so it should be quite easy to do.

All-in-all $500 savings for 5 min of work… I’d say it was a pretty good return on my investment! 🙂

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The price of admission

November 26, 2011

So I finally got my quote back for all the ULS parts this week. It came in quite a bit higher than I anticipated. While most of the items are tolerable, some aren’t. [all prices are Canadian, and don’t include the 13% tax I need to pay as well]

Optics: $460

This is where I expected to spend the most. So I’m okay with $460 for replacing everything in the optical path.

Timing Belts: $140

A bit pricey, but they are kevlar re-enforced timing belts, so I’ll let it slide.

Idlers: $90

Ok, these are a bit rich, I’ll need to see if I can find an alternative source. But in the grand scheme of things, just a drop in the bucket, so if I must, I can live with it.

Bearings: $200

Ouch! Not much I can do here, unless I can find them cheaper from another supplier. or machine my own alternatives. There are some custom components involved, so perhaps justifiable.

Lens/Focus carriage: $400

Thank the gods I was able to salvage this! Chalk Fridays efforts up in the WIN column for a second time 🙂

Engraving table: $500

This was an unexpected price, given that the engraving table is rather uninteresting. I will have to see if I can salvage the old one, by removing the top aluminum sheet, and replacing it. [probably next Fridays efforts/post]

X Rail: $370

WTF!!! This is an insane price. The X Rail is simply an anodized, light weight aluminum extrusion that is 27 inches long. Unless I can find some serious savings elsewhere in this project, it’s pretty much a given I’m going to have to engineer my own alternative solution. Sadly this one part is also a major hinge-pin for the entire project.

 

All-in-all the grand total came to ~$2,150 plus taxes to replace the optical & mechanical parts. Let’s not forget there’s still the control panel, and motors at a minimum that need to be replaced as well. Now thankfully I have salvaged the lens/focus carriage, and I’m hoping to salvage the cutting table, so that will bring it down to ~$1,250 + taxes, still up there, but much more manageable, and in the ball-park of what I was expecting.

Unfortunately life has thrown a couple of financial curve balls at me the past few weeks, so I’m going to have to re-visit my budget, and probably spread the costs out over a greater period than initially anticipated. My initial time line was to have all these bits in place by January, but now it will need to be quite a bit later than that, unless a money tree sprouts up in my back yard.

I wonder if I can start a charity to save a sick and dying laser? 😉

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One less thing

November 24, 2011

Well today I decided to try and salvage the flying head that carries the #3 mirror and focusing lens. I had pretty much written it off, as it was partially encased in molten glass & plastic. It also fell into the fire, so I assumed the worst for the parts of it that I could not see.

If you don’t remember from the earlier pictures, this is what I started with:

I grabbed some pliers and started tearing away at the globs of plastic & glass. To my surprise most of it peeled away fairly easily, with just a few stubborn bits left stuck to the head. Once I got the bulk of it off, I tried to remove the lens/mirror assembly via the two thumb screws on the front [it is mean to to be easily removed/replaced]. Unfortunately it didn’t want to budge. So I proceeded to fully disassemble the head, by removing every screw I could find. Eventually it all came apart. Some plastic had mad it’s way inside and was gluing the lens to the case. A little prying and I got it free. After that I cleaned each part individually, mostly by gently scraping with a bare box-cutter blade.  I then re-assembled it.  And this is where it’s at now:

While it doesn’t quite look like new, it is a stark contrast to what it was before.  With the exception of some chipping and pitting on the anodized coating, the head is in very good shape, and appears to be totally usable. The optics within are another story, they are unrecoverable, but easily replaced now. The 3 arms on the head also normally have rubber bearings/wheels on them, these need to be replaced as well [also easily done]. Luckily, the spring loaded mechanism on the 3rd arm is working perfectly. I may get the head re-anodized to give it a like new look, it will depend on the cost to do so, and how many other parts need/warrant anodizing. Having said all that, I am ecstatic that I was able to salvage the flying head, it is one less item I will need to buy or engineer to replace.