Making Skins #74 - Brisbane Australia

[Richards]

If you visit www.automationdirect.com and click on proximity sensors, you'll be able to download a data sheet that shows the internal workings of their sensors. The 12mm series (AM1-AN-2H model number) has a common data sheet. Compare the 3-wire sensors to a transistor and the two wire sensors to a diode.

I've used a nine-volt battery to test sensors, although a 12VDC to 24VDC power supply is better. All of the sensors that I've tested have worked fine with 9-volts (meaning that they've worked "fine" enough that I could check polarity and sensing distance - I would never use a 9-volt power supply to run an installed sensor.)

[Surfcnc]

Hi Pablo

The term I have used -12V is not the correct one. I believe it is referred to as 0V.
Far better to propagate the correct term than my own homespun understanding.

Ross

[Surfcnc]

Made a few more bits up for the machine.

The Cable Chain Supports
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The Car Stoppers
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The Z Spider Welding- used a magnetic clamp to hold the motor bracket straight but it still needed trueing once the heat got to it.
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Also bent it straight using this technique and cut and welded the small tab.
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Finally got the Dust Collector Pipes - Just in Time now Bill Pentz is on the Mechmate forum
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And a Ebay Bargain on Cable Glands from the UK
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Regards
Ross

[Alan_c]

Nice going Ross

I fear your X cable chan support may be wrong (unless you are using a reverse installation) usually the two supports look the same with the main bracket on the right - only the size differs.

[Surfcnc]

Hi Alan

It seems your careful attention to detail has picked up something my sometimes random approach to things has missed, hehe.

What has happened (on closer inspection) is that the bending has been done the wrong way! Attached is a pic that sheds light on the issue.
Hmm, probably going to need another one of those X cable chain shelf bracket sets bent the "right" way now.
Thanks for your post giving me a chance to get going on the fix that bit quicker.

IMG_0923.jpg

Regards
Ross

[Surfcnc]

Hi All

David has given us the details on how to wire up three PNP NO and one NPN NO proximity sensors without relays at http://www.mechmate.com/forums/showthread.php?t=2857

I have made an inquiry with the eBay seller "auspicious.e" and while they do not list the PNP sensors for sale on Ebay they were able to obtain them.
Four sensors where around $50 USD delivered to Australia.

My relay to test the proxy wiring as per Sergio's schematic is speeding from literally over the hill at the speed of an aging turtle with a bung leg.
In the coming week I hope to finally see the part and get on with that test.

Regards
Ross

[Surfcnc]

It was a clear sunny day, so time to start some of the bigger pieces through the painting process.

I have to say I lingered in the back yard as it was so nice in the sun.
The photos actually make the paint job look far better than it is in the flesh.
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The missing/ not ordered / reordered/ forgot to ring you/ we are stocktaking, relay finally appeared after doggedly following up the supplier.
A photo for those who might be inclined to copy the part number or style of relay.
IMG_0929.jpg

This is the pic that Sergio sent me of his relay he used for his proximity sensor wiring.
The only real difference is that in Italy they have the good sense to put the printing on the relay the right way up or maybe I got the down under version.
All a matter of perspective I suppose !!

Sergios Relay.jpg



I forgot to take a photo of some of the other parts I was painting black and hanging on the very Aussie Hills Hoist (rotary clothes line).
If I remember tomorrow I will include a photo of this alternative use for a domestic appliance.
All the parts are spending a day or so in the sun to set up as the paint is so easily damaged when not properly dried.

Regards
Ross

[Regnar]

Ross, be careful of setting the parts out in the sun. I cant remember it was here or on another forum but I do remember reading that the steel heats up to much in the sun and will boil/bubble the paint off the steel before it can cure.

Wait until you have to read that relay when its mounted on a din rail. You will be happy for that down under version

[Surfcnc]

Thanks Russell

KenC offer this advice on the MM forum but I have not found this to be an issue.
As a check though, the current temp in full sun of the metal is 28 deg C, this temp is not high enough to boil the paint.
On a summer day 60+ degrees C would be possible and that may indeed damage the paint film.

The printing on the relay as you rightly point out is for the "peering in to the enclousure from the top" sceanerio.
That is exactly what I will be doing but hopefully not for toooo long, hehe.

Regards
Ross

[Surfcnc]

As promised the parts out to dry ... and a sheet too.

IMG_0931.jpg

regards
Ross

[AuS MaDDoG]

Ross!!

I'm impressed mate, you are starting to get close we might be painting our parts this coming weekend too if the weather is good to us

Keep up the good work!!
Cheers
Tony.

[Surfcnc]

Trimmed up the spindle mount today. The "standard issue" 80mm mount is a little too wide for the Z slide and needs some clearance for the V rollers.
The mount is marked with permanent marker then scratched with a scribe to give a high visibility cut line for the saw.
I actually cut away a little more than the roughed in marks on the spindle mount, those marks were just to show how to clear the rollers.

Original Mount
Original Spindle Mount.JPG

Trimmed Mount - An 80 tooth timber drop saw blade cuts it like butter, but produces a shower of swarf, so wear eye protection if you use this method.
IMG_0932.jpg

Still Painting Bits - The bottoms of the rails this time.
Three of them have been masked off where the racks will go.
This time I have tried a no undercoat enamel and a paint additive to see if it adheres any better than some of my other parts have.
To prep the rails I sanded all the factory scale off back to shiny metal with a 80 grit then 120 grit flap disk (Metal Head recommended these earlier in my build history).
IMG_0934.jpg

Last night I also repainted the x beams of the table base to cover up the fire marks (yes the fire, from welding my gantry in place on the beams on some paper spacers, haha), the impact marks and other assorted damage.
I used a tiny foam roller to apply the hammertone paint and it did a great job.
It worked so well if I had my time again I would use the roller for all the metal top coat.

Regards
Ross

[MetalHead]

I am a believer in the foam roller method.

I have used it to paint my Dynatorch Plasma machine and it works great. I used it and little plastic mixing cups on the painting isle at BigBox Hardware (orange or blue you choose ) and a pack of the plastic drop cloth to go under the items being painted.

Once finished I toss sponge part and save the cup and handle until I finish with that color. Then I toss the cup. I also recycle the plastic drop sheets. They wad up read small.

No over spray and the finish is fine (really !!!) give it a try. Setup and tear down is quick and you wont catch grief for overspray on everything in the garage/shop

[Surfcnc]

The painting continues - every time I look at something I give it another coat !!

First up - Thanks Alan C, I got my replacement part from Lasercentral, they were very good about the replacement part, even although it had been some time since they made it.
Bent The Correct Way.jpg

Put my spider together again after painting and mounted the short piece of rack on the Z slide.
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Finally got the rails painted and put them up on the machine to dry for a while before I start to straighten and level them.
I was quite pleased with the colours once I saw them in place.
IMG_0946.jpg

Regards
Ross

[Surfcnc]

Aus Maddog and Skippy are pump and pipe experts due to their salt water fish tank hobby. Tony gave me a look at his reef tank and it was quite spectacular.
Both the boys recommended the Aquabee pumps but I had some time today and just started experimenting to get one more thing off the list.
I found a tube to fit the spindle inlet and before I knew it I was in a pet shop buying a pump to do some further tests !
Seems that pumps for the water cooled spindles have been a stumbling point for many.
Given this I oversized the pump on some of the other wattage ratings I had seen on the forum and threw thoughts of low power consumption out the window.

First was the pipe to distribute the water - in the end a 5mm internal diameter clear plastic tube was the correct size to fit the 2.2 kw Chinese spindle inlet and outlet ports.

Second was to adapt the pump 19mm outlet to the 5mm tube. This was achieved by sleeving over the outside of the pipe with larger diameter pipes until it fitted.

Third test if it leaked, thankfully it was a dry as a bone, otherwise I was going to set it all in an epoxy mold.

Fourth was to test the flow rate. The pump used as a 45 watt 2200 l/hr with a maximum head of 2.5 m.

The end result was a flow rate of exactly 500ml per min at 1.0m head through 7 meters of the 5mm internal diameter tubing.
Passed the 375ml per min "beer glass" standard the forum members are using as an adequate flow rate for cooling.
The pump easily cleared any bubbles in the line and quickly settled down to an uninterrupted flow.

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Regards
Ross

[KenC]

Ross, This can work but you must be careful with a few things.
Are you going to install your pipes in your cable chain? 7m might be a bit too short to go into the cable chain. Is your return pipe 7m too? so a total of 14m pipe is involved? AND the viscosity of the liquid/water will change when you add coolant to it & that will further reduce the flow rate as well...
Industrial pneumatic PU pipes are great for this job, OD6mm tubes will fit the chinese spindle snuggly & I use OD8mm for the supply & return pipe, use 2 8 to 6mm push on reducer just before & after the spindle. They aren't any more expensive than aquarium pipes & they have suitable push on reducer, elbows, swivel elbows... & other fitting that are affordable too.

[Surfcnc]

Hi Ken

I purposely ran the whole run through a small pipe to see what the effect of the maximum restriction would be.
Indeed the return is also 7 or so meters and I have not modeled this as that was all the pipe I had on hand.
The 7 meters estimate came from Doug Ford's comments at http://www.mechmate.com/forums/archi...php/t-505.html, 7 meters has to be pretty close I'd say especially for a test situation.
My objective is to get the required flow rate of 375ml /min into the spindle for cooling, so as long as a solution provides this I will be happy.

There is a buffer of 125 ml/minute or 33% remaining in the system.
While it is pretty unscientific, my gut feel is that it will readily meet the criterion.
Once I get some more pipe and mix in some Ethylene Glycol will give you a new flow rate.

Regards
Ross

Regards
Ross

[AuS MaDDoG]

Nice Work Ross!!

Check out these fittings http://www.johnguest.com/range_spec....FIT&rs=1&id=17 these are the push together "John Guest" fittings we use, and the plastic flexible tubing that is used with these, fits straight onto the spindle coolant fittings. There is a guy on Beaudesert Road just of Grannard Rd that stocks a full range of fittings and tubing.
Pneumatic/Hydraulic shop think it might be Tony Powers.

Cheers
Tony.

[Surfcnc]

This looks like it - Hose and fittings !!

Hose fittings.jpg

Ross

[AuS MaDDoG]

Yep!!

Thats them!! your on too it!!

Cheers
Tony.

[KenC]

Yes, that's the right way to find out if the pump really works.
My machine is a tat longer then normal, but it is not far off. I used up ~25m of tubing in total. so I hope you will source enough tube for your installation.
375cc is good enough, but 300cc/min can still keep my spindle cool (35C). I recon the long tubing does radiate some heat while the coolant travels in the whole journey.Mine is running about 350cc/min
For my aquarium pump experience, the flow rate will deteriorate over time, a short 3 months & mine is down to a trickle. & 50cc/min could still keep my spindle alive... barely... 500cc will give a longer service life for you assuming that it's performance deteriorate like mine did...
Be careful with pure glycol, it is more viscous than just neat water.

[Surfcnc]

Ken

Been checking up on your concerns re viscosity and found these engineering tables http://www.engineeringtoolbox.com/et...col-d_146.html

According to this source
1. the hotter it gets the more it flows
2. a reasonable maximum estimate of combined pressure and flow reduction at 40 deg C for a 50% mix of Ethylene Glycol and water is 114%.

Your comment regarding the decrease in pump performance over time is certainly something to factor into the design side of the cooling system - thanks.

Regards
Ross

[KenC]

We all paid a handsome amount for the spindle even though it is a steal in comparison to non-chinese equivalent.... but it is money after all, it breaks my heart to see equipment damaged in any circumstances...

[Gerald D]

Ken, the serious aquarium guys pay more for their fish than the price of a spindle - they use decent pumps to keep those fish alive.

[KenC]

I'm not a serious aquarium guy, but I do keep Arowana in captivity... yes, a 6" little fish fry cost more than 2 spindles...

[PEU]

Originally Posted by Surfcnc

Attachment 10037
Attachment 10038

I purchased a slightly larger pump probably made by the same manufacturer but branded differently for the local market.

When I was testing the spindle I left a 24L paint bucket full of water running the whole afternoon at 8K RPM it got warm, I would say 30~35C after at least 5 hours continuous. I'm sure if I use a larger tank this wont happen.

Mine is rated 2700L/hour and with 2 meter long flexible pipes for the test it was too much pressure and you could hear the impeller rattling even underwater. My guess was that when I build the MM with way more meters of flexible pipe the pump will need the pressure.

[Surfcnc]

Hi Pablo

I agree probably not an industrial grade pump but it seemed to give a very good result anyway.

Also put a 12m pipe on the outlet - no difference in flow.
Think I know why but the result speaks for itself.

Regards
Ross

[Surfcnc]

In another post I asked everyone how they straightened and leveled their rails.
The best suggestion in my eyes was Gerald's method of using an aluminium extrusion and a gauge.
I have some well used aluminium screeds but did not trust these to be straight after much work both in the cement and out of it.
In the end a 6.5m 75x25x2.5mm length of aluminium extrusion was the option I took to get a good straight edge (two actually after it was docked in half).

Here is the basic setup, soft drink cans trimmed into shims, the extrusion and a set of metric automotive feeler gauges.
Rails 2.jpg
Feeler Gague.jpg

Using the feeler gauge I was able to EASILY measure any gap between the rail and the 25mm face of the extrusion down to ridiculous increments.
The resolution I choose to work to was 0.1mm as that was the thickness of the shims I was using.
The difference between a .15 and a .10 low spot in the rail was night and day when checked (literally done by feeling) with the gauge.
Now that I have the method and the tests done, I feel very confident of getting a great result with the rails.

For those inquiring minds that may suggest the extrusion may not be straight, Gerald also suggested setting up with opposing sides of the extrusion to check if the result is reproducible.
I checked using this method and got very good reproducible measurements, the two sections docked from the 6.5m length also checked well against each other.
For the even more inquiring minds, this is an inferred measurement of straightness not a direct measurement of straightness but for my purposes it is more than sufficient.

Thanks to everyone who gave their opinions and techniques on my question about the rails.

Regards
Ross

[tangocharlie123]

Ross thanks for the photo's and how you and Gerald did it now just need to get started.

You should keep the RHS and rent it out.
See your machine can earn you money before you start.

Thanks
Peter

[Surfcnc]

Greetings Pete

I see you are from Brisbane, must be something in the water here that makes people inclined build CNC machines.

Regards
Ross