Constructing Janus, by Dirk

Post your build logs here

Re: Constructing Janus, by Dirk

Postby naPS » Sat Aug 13, 2011 4:25 pm

Dirk - totally typical on both questions. My laser came with both little tubes not present, and the little metal ring definitely isn't on center in mine either. Works great though.

Check a few of the threads on how to get the small sections of tubing on to the connections on the laser. It will save you lots of headache. It basically entails throwing the small pieces of tube in some hot water for a few seconds to soften them up.
naPS
 
Posts: 202
Joined: Sat Apr 09, 2011 1:53 am

Re: Constructing Janus, by Dirk

Postby dirktheeng » Sat Aug 13, 2011 5:59 pm

naPS wrote:Dirk - totally typical on both questions. My laser came with both little tubes not present, and the little metal ring definitely isn't on center in mine either. Works great though.

Check a few of the threads on how to get the small sections of tubing on to the connections on the laser. It will save you lots of headache. It basically entails throwing the small pieces of tube in some hot water for a few seconds to soften them up.


Thanks for letting me know. I will start assembling the laser here in a little bit. Jay is stopping by this afternoon with a temporary power supply so I can get the pump running and test this out.
dirktheeng
 
Posts: 616
Joined: Thu Sep 09, 2010 4:49 pm

Update to monitor arm

Postby dirktheeng » Sat Aug 13, 2011 6:41 pm

All,

I was thinking about the design and was concerned about dust/dirt gettign into the clutch and keeping the surfaces from contacting eachother and I also want to improve the coeffficient of friction. So I began to think about products and applications where high friction is needed to see if I could find something that woudl work well for this application. The first thing that came to mine was non-skid tape that you can put down on steps and stuff. That is like very tough sand paper, which would really improve the surface friction without creating any "sticky" adhesive like sufrace so that when the pressure is released, it doesn't stick. I was prepared to make a desing with this and accept the potential marring of the surface of the clutch plates, which isn't a real big deal, but it will wear more quickly. However, I found non-abrasive non-skid tapes as well and they are pretty cheap.

I want something that is rubber coated, textured, and thin. Rubber increases friction coefficient and is somewhat compliant to flex around anything that gets in the clutch. Texture helps air get behind the plexiglass to release when pressure is taken off and gives dust somewhere to go/collect that doesn't affect the gripping power. Thinness is beneficial because I don't have a lot of room but rubber is also very flexible and shears a lot under load... the thinner the tape is, the less it will shear under load which has the net result of making the joint stiffer.

I found handrail grip tape that seems to meet the above requirements. I found a couple that I may end up using. Here are a couple pictures of the textured surface.

This is 3418 Anti Slip Tape from AntiSlipTapeShop.com:

3418 Anti slip tape.jpg
moulded, pimpled surface grip tape
3418 Anti slip tape.jpg (14.2 KiB) Viewed 10408 times


This tape has a moulded surface that is a bunch of domes... It is much like a ping pong paddle surface (and yes I looked at that too... it was very expensive for what you get). It is 0.023" thick and will have the advantage that all the dome heights should be very uniform, so it should allow for good, uniform contact. A 52"x12" piece is $13.20 with free shipping.

The second one I found was Black Resiliant Grip Tape:

BlackResilientGripTape.jpg
Black Resiliant
BlackResilientGripTape.jpg (16.05 KiB) Viewed 10408 times


The surface does not look that uniform, which could cause some problems, but I don't know what scale this is. It is thinner than the other stuff, 0.02", but not much. They do say thaat this is the most grip for a non abrasive tape. a 47"x12" piece is $11.00

Either option will give me more than enough material to get all the clutch rings I need and they are adhesive backed with really strong adhesive.

Does anybody have any other suggestions?

Here's a view of the shoulder clutch with the tape in place.

ShoulderClutch2.jpg
Shoulder Clutch Update 2


I added slots in the inner clutch plates to help air get in behind the clutch so they release quickly and easily (may also help bite the tape when pressure is applied). I conservatively estimate the coefficient of friction to be about 1.5 with these materials, but it is likely to be much higher. At that kind of friction, I actually only need 1/2 the plates in the clutch. However, I don't want to end up putting too much stress on the plates and get cracks. Plus this gives a margin of safety.
dirktheeng
 
Posts: 616
Joined: Thu Sep 09, 2010 4:49 pm

Re: Constructing Janus, by Dirk

Postby quadmasta » Sat Aug 13, 2011 9:07 pm

Couldn't you make this a lot less complicated with a ratcheting mechanism? It wouldn't be infinitely adjustable but it'd be way less complicated and prone to failure.
quadmasta
 
Posts: 135
Joined: Mon Apr 18, 2011 3:01 pm

Re: Constructing Janus, by Dirk

Postby dirktheeng » Sun Aug 14, 2011 1:07 am

quadmasta wrote:Couldn't you make this a lot less complicated with a ratcheting mechanism? It wouldn't be infinitely adjustable but it'd be way less complicated and prone to failure.


sure... but even a 1 degree ratchet will mean that the best resolution you can have is 1/4"+ at the elbow, and more than 1/2" at the shoulder. At 1 degree resolution, your teeth on a 3" diameter gear are almost too small to really cut with confidence that they won't melt or burn out during cutting... plus they won't last long if it get's positioned often being so small.
dirktheeng
 
Posts: 616
Joined: Thu Sep 09, 2010 4:49 pm

new Parts and Assembly

Postby dirktheeng » Mon Aug 15, 2011 10:06 pm

I had some time to work on the laser this weekend. I got he power supply installed on the steel shelf I made and I also fitted the laser tube with the plumbing needed to bring the water too it from outside the case. I installed some quick connects that will end up just outside the case so I can quickly take the laser off the laser cart.

Here's a few pics:

DSCN4135.JPG
Laser with plumbing


DSCN4136.JPG
Quick connects


DSCN4138.JPG
Laser PS 1


DSCN4139.JPG
Laser PS 2


I also received the swiftech pump/radiator/reservoir combo unit and the koolance flow meter. These will both end up in the laser cart when I get that done. The fan's have not arrived yet, nor has the ATX power supply. Jay lent me a 12v PSU so I could get the pump running until that other stuff shows up. Eventually, the pump and fans will be controlled by an arduino and the flow meter will be read by it and send the data to Mach3 and/or sound an alarm.

DSCN4141.JPG
Swiftech radiator with pump and flow sensor


next test will be firing the laser and doing an alignment. I have the right diameter laser pointer on order so I can do a rough alignment my mirrors with the fixture that Ben sent me.

The end of this project is in sight now and I'm pretty excited... but is it really ever going to be "over"? I don't think so... that's part of the fun of it.
dirktheeng
 
Posts: 616
Joined: Thu Sep 09, 2010 4:49 pm

Fans and Power Supply put together

Postby dirktheeng » Wed Aug 17, 2011 12:14 am

All,

I came home today and my wife was at the door with a couple packages for me. One came with the ATX power supply, silicone tape, and some 1/4-28 nylon nuts (which I no longer need) and the other came with the 120mm fans. Tonight I assembled and tested the fans on the radiator. I made a custom connector to power the fans, transmit the PWM signal and read the tachometer. The connector also houses the PWM and Tach signal to the pump. When the pump/fan recieve a PWM less than 20-30%, they will still run at a minimal (not insignificant) speed. I left the pump on the molex connector because it draws about 1.5A which is more than I want to push through the connector I made. All three fans draw less than 1 amp.

To make the ATX PS run, I cut the green and black wires and soldered them together (the green is the power switch lead, and has to be shorted to ground for the power supply to turn on).

Here's a pic:

DSCN4142.JPG
Fans and Power Supply Hooked up


Sorry Jay... the ATX supply arrived before I had a chance to get a test done. I appreciate you letting me borrow the 12V supply though!
dirktheeng
 
Posts: 616
Joined: Thu Sep 09, 2010 4:49 pm

Monitor Arm Update - clutch plates v1

Postby dirktheeng » Wed Aug 17, 2011 2:34 am

Well,

I spent some time fiddling around with the design of the levers to press the cluch plates together. Here's version 1:

ShoulderClutch3.jpg
Pressure Plate


You can see the pressure plate here... it is reinforces to transmit the force to the clutch stack.

ShoulderClutch4.jpg
Clutch disengaged


Here you can see the method to disengage the clutch... there will be a magnet attached to the lever and an oposing electro magnet. When the clutch is engaged, the electromagnet will be off. The electromagnet will have a feromatgnetic core so when it is off, the magnet will be attracted to the metal core. When the electromagnet is on, it will be such that N is to N or S to S so it repels and forces the levers up to the position which relieves the pressure. The advantage of this design is the ability to highly magnify a small force. I can also create shims to adjust this.. paper and or card stock will work fine.
dirktheeng
 
Posts: 616
Joined: Thu Sep 09, 2010 4:49 pm

It lives! Finally! Here's the proof

Postby dirktheeng » Thu Aug 18, 2011 1:42 am

All,

another exciting day today! I got the laser test fired. I mounted the laser in the holder and made all the connections, filled the system with water, and let her rip. It worked first try.

Here's the proof:

DSCN4146.JPG
results of first test


The wire connections to the laser are now permanent. I can disconnect both ends for service. I went back and added some connections on the ground and led the wire through the frame slot using one of the slot covers I had. Afer tying and lashing the wire to the lead with narrow guage wire, I used some of my wife's nail polish to glue it to the assembly. After thinking about it, I probably should have used my trusty super glue, but this is ok too... at least I could see where I applied it. I also got some of that self sticking silicone tape and really wrapped the connections tightly. That stuff is awesome!!!! It doesn't come appart easily and there isn't any adhesive.

The only bad thing that happened was one of my fans got ruined. I cought it on the corner of my frame when I was trying to stand the radiator up and it broke off one of the blades (it was running when it hit the corner). I broke off the one directly oposite to it to balance it for the time being, but I have to replace it eventually. I will also be ordering some fan grills to make sure this doesn't happen again.
dirktheeng
 
Posts: 616
Joined: Thu Sep 09, 2010 4:49 pm

Re: Constructing Janus, by Dirk

Postby metalman » Thu Aug 18, 2011 2:25 am

Congratulations on the successful test fire. Janus comes to live. To bad about the broken fan blade. As long as it is still balanced it should get you by.
metalman
 
Posts: 33
Joined: Tue Aug 31, 2010 3:03 am

PreviousNext

Return to Build Logs

Who is online

Users browsing this forum: No registered users and 5 guests