Making Skins #74 - Brisbane Australia

[Surfcnc]

Have been working on getting the rails level then straight with the alloy extrusion. Very pleased to say it all went really well.

The coke cans slivers proved to a very effective shim.
First I packed them up and secondly I counted them and then cut new ones at 25 x 30 mm to fit exactly under the rail.
The photos below show how it was done and how tidy the end result was (the small silvery line under the rail are the shims in place).

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Next I put the gantry up on the rails and rolled it up and down to check how it sat.
After that it was more a process of listening to the noise of the gantry as it rolled to check if it was true.
I heard a few bumps as it rolled along and these turned out to be some tiny bits of paint on the rail.
Given this I hand sanded the V on the rails with some 320grit sandpaper (quite a bit) and ended up with a finish that showed no scratches at all.

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Regards
Ross

[Surfcnc]

Mounted my cable chain brackets and then the cable chains themselves.
The bracket that holds the X cable chain to the gantry was made out of some 6mm aluminium plate I had lying around and it turned out very nicely.
I had to shorten up by X cable chain by about 300mm so I have a few spares or something to use on a later project.
Starting to look like the part !

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Trashed a few pinions as I learnt how these things are done.
The photo attached is the first victim on the block.
"He" was followed by two more before I figured out the way to get the bore concentric was to use a metal lathe.
All part of the learning experience and learning I am.

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Small Wood Lathe Purchase - 4th Axis Maybe?

I have purchased a small wood lathe that gives me a very sedate 254 mm maximum swing but it has a meter between centers.
My reasoning is that a table leg is around 900mm max so as a starting point for a minimum price it fits the bill.
Found some floor stock in Adelaide for a good price - thats around 2,000 klm from my door so no one can say I did not look hard enough, haha.

The lathe itself is a Chinese model that is re branded around the globe (the same as the small machine in the videos but with an extension bed).
The inspiration for the conversion I might undertake later when the machine is finished came from these two videos.

http://www.youtube.com/user/mikescnc.../3/Wj1BN7JGvek

http://www.youtube.com/user/mikescnc.../2/f1wP4vbkJwQ

It does not look like he has finished his 4th axis project but the basic concept looks sound.

Regards
Ross

[Surfcnc]

Greetings

Tonight I mounted the spindle mount to the Z slide.
It took about 30 minutes to drill the Z slide the tap the 4 M6 socket head screws holding the bracket to the Z slide... and plenty of time of measuring and thinking !!

Here are some pics of the end result.
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One of the Z slide limit stops is done but I need my pinions before the other can be put into place.

The measuring and thinking all centered around how far the spindle could retract up into the gantry.
Initially I thought that if the collet of the router was level with the bottom of the gantry all would be fine.
Upon a bit more thought I realised that where the collet was was also dependent upon where the spindle was in the bracket, so just lining the collet up was not enough detail to use alone.

The pics show the spindle mounted in the bracket, set like this it will retract to level with the underside of the gantry, however the spindle can be further adjusted away from the base board by another 42 mm.
This gives the ability to have a cutter mounted and still get the full height of the machines envelope to cut with.
Specifically I am thinking of cutting foam surfboards "up there" at the top of the stroke. For this to work of course any dust shoe would need to be removed or modified in some way.

No point in having it retract way up high and not bottom out well below the spoil board top, so using this setup the collet will bottom out at the top of the base board.
The third and fourth photos show the detail of where the top of the 2.2kw watercooled spindle extends to on the z slide for those who might be interested.

Thanks to Matty Zee for the photo he sent me many months ago explaining how the collet on his machine retracted relative to the bottom of the gantry.
These things certainly help.

Regards
Ross

[Surfcnc]

Sanded the ends to a bevel.
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Clamped them up with the splint rack and a few G clamps, then welded the bottom and each side of the racks.
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Ground the welds flat.
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The joins ended up good and strong.
As I did them I also made sure the pinion rolled smoothly over the join.
One join required a redo and I have just one more X rack to do.

Hope you enjoy the photos of the process.

Regards
Ross

[Gerald D]

Good photos, good welding

[Surfcnc]

Hi All

The lathe I purchased arrived today. For the moment it is a "manual forth axis" that is, you stick a sharp chisel into it and do it yourself.
No fancy CNC electronics anywhere near this little fella just yet but some time in the future, it might end up as an indexer (if that is the correct term).

The lathe came with a live center, headstock spur, faceplate, various Allen keys and an extension bed not shown in the pics.
Buying a 4 jaw selfcentering chuck, lathe chisels and a No2 MT jacobs drill chuck - well that cost what the lathe did in the first place !!

Parts of the wooden packing case ended up as a handle for an old garden trowel and a tool holder.
Already earning it keep - not exactly.
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Kind regards
Ross

[Kobus_Joubert]

Looks nice and sturdy Ross. You should be able to fit a 120 tooth gear on the left there for the stepper motor.
Good luck with the conversion

[Surfcnc]

Hi All

My progress has been slow especially by comparison to the Aus Maddog / Skippy dual table build.

I had a clearance issue with the Nyloc nut that holds the Z axis motors and the rail itself. After completely removing the perfectly leveled and straight rails, I realised that all I needed to do was to reduce the 10mm nut to 8.5mm by sanding it down on the linisher. It just took me a month or so to get back to doing the rails again !

The joins in my rack have been a mixed bag, some perfect, some acceptable and one needed a redo. So still trying to get that right before doing any wiring. If I had to say what was causing the problems was that I had not let the pinion drop fully to the bottom of the tooth in the rack, this causes a bump as the pinion rolls over it. I can confirm the double sided tape sticks like crazy after removing one Z rack to fix a join up. It was NOT going to fall off, haha.

I see Aus Maddog has the Vectric Aspire software rolling, so good to see you have even the next phase of development firmly in your sights.

Also see that Red Boards has a substantial table base underway. Don't worry about the grinding Red, mine took me ages to "massage" into an acceptable state. All part of the learning curve.

Still really enjoying the whole project and have really got into the engineering aspect of the build.

Regards
Ross

[AuS MaDDoG]

Hey Ross!!

I was wondering when you were going to give us all an update thought you might have been busy with work.
we have been having similar fit issues with the racks, roll the pinions over them and they appeart to be fine but once fitted in place with the pinions locked on its a whole different scenario with little bumps being felt whilst the gantry or the car are moving. I have decided to wait it out and see what they are like when the motors are moving them under there own steam.
Seriously thinking of replacing our rack to the 3m lengths that are available to avoid any joints so if you are interested let us know.

Anyway on with the work and I look forward to more regular updates from you again

Cheers
Tony.

[Surfcnc]

Gidday Tony

After a further go at one rack today, the worst join was better but not perfect.
Called TEA and they had one 3m length of module 1 rack in stock.
When I first looked many months ago, nobody had 3m lengths available, so at that stage one join in a 3m length was unavoidable.

I have ordered 1 x 3m rack for one side of the X axis and have left the other side with the 3 x 1m lengths joined.
Did some rack dentistry on the joins and made some improvement by reshaping the intersection with a file and a diamond hone for the valleys.
The most infuriating part is the perfect join is between two pieces of stock with the biggest dimensional variation.

TEA do not have any more 3m lengths, so buying one as I have is probably setting myself up for more grief as the racks are not a matched set - but no guts no glory.

Between doing the rails twice and playing with the racks, I certainly have wasted some time, but it all still qualifies as good experience !!

Regards
Ross

[AuS MaDDoG]

Ross,

Did TEA indicate if they were going to be doing any more of the 3m long racks??

Cheers
Tony.

[Surfcnc]

Hi Tony

Yes they did indicate that it was one of their stock items and that they would reorder now stock was out. I think the stock order may be done every month or so but you might like to check with them as xmas is creeping up on us.

Regards
Ross

[MetalHead]

If anyone there is looking to buy rack now would be a good time to commit. This way they can order enough for everyone in one order and maybe get you all a better price.

[Surfcnc]

The 3m section of rack arrived today, packed in a very long and sturdy tube.
I have painted it this evening and will mount it tomorrow. Sure makes it easy in comparison to joining 1m sections of rack BUT the flip-side is that it is far more expensive.

As per Mikes suggestion, I will call TEA tomorrow and ask about some consideration for the MM builders if they identify themselves as such.
See how we go, if they agree I will post the full details of the company to act as a permanent sign post to their business here in Australia.

Regards
Ross

[Surfcnc]

All Right - starting to look the goods now.

I attached the 3m single piece of rack (3015mm for those who might be interested in the exact dimension) onto the machine tonight.
After rolling the gantry down the machine I heard a now familiar clunk as the pinion rolled over a small lump !!.
After a bit of cleaning of a few teeth with a carbide point the gantry finally rolled very smoothly - you beauty !

I have not called TEA yet as Australia was busy at the races today and nobody likes a call when the Melbourne Cup is on.

Any way the attached photos tell the story.
I am very happy with how the Mechmate has turned out so far.

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Now to wire it up.

Regards
Ross

[Alan_c]

Well done Ross, looking good

PS watch those trolley jacks, they seem to be breeding under your table

[Surfcnc]

Hi Alan

Your Fleischman Chair was really interesting, I read a number of chair blogs for further inspiration after seeing you perched happily on your creation.

Thanks for the comment about the machine and I will set some baits under the table for those pesky trolley jacks.

Regards
Ross

[Surfcnc]

Due to the position I intend to mount the VFD, dust filtering and cooling was a must.
My solution was to fix the VFD into an electrical enclosure then use a 240V AC fan and car air filter element to create a positive pressure enclosure.
After a few sums on passive heat radiation from steel enclosures there was no way the VFD could go into a sealed box.

My xray vision has become weak with age, so a window to see the VFD screen was also a must.
After pricing an enclosure window, it was immediately obvious that making my own was going to be far cheaper.
A piece of HDPE plastic routed into a "picture frame" and another piece of clear acrylic as the window did a great job.
After cutting out a hole, I just pop riveted the assembly to the enclosure door.

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In previous posts I have discussed solid state lighting (High Power LED's).
For those interested attached are two pics of my DIY work light made up of 3 x 10 watt LED's.
This light draws a total of 60 watts and no other lights were on when the last photo was taken.
Imagine the same room lit by a 60 watt incandescent globe and you get the idea of how efficient solid state lighting can be.
It is also cool in front of the light, a nice change from the 150 watt floodlight I was using !
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On now with some planning to mount the boxes to the side of the machine.
Some words Gerald wrote about the serviceability of the boxes on the side of the machines has made me think.
No promises but I will try to have them swing up to horizontal for servicing to avoid laying on the ground.
We shall see how that one pans out.

Regards
Ross

[Alan_c]

Neat VFD box and I like the light, but maybe I am missing something here, why do 3 x 10 watt LED's draw 60w? where does the rest of the power get consumed?

[Surfcnc]

Hi Alan

The 60 watts was measured at the start of the lights 12 volt laptop power supply.
So the PSU loses some energy in inefficiency, plus I am using 3 simple 5 watt resistors to control the amperage.
The resistors only account for 2.7 watts lost in heat and the laptop bricks are generally pretty efficient.
The light has a 60mm cooling fan I put on it as it heats the alloy to the point where it is uncomfortable to touch.
My best "guess" is that the major proportion of the missing wattage is lost in heat.

As an aside, this waste heat is readily dissipated to the surrounding air.
The solid state lighting does not produce radiant heat in the infrared spectrum like a filament light does.
Despite the local heat losses, in front of the light remains cool.

PS Good question.

Regards
Ross

[mrghm]

Ross,

lights are a great idea, those "work" lights get hot then you knock it and the globes blow.

[Alan_c]

Thanks for the explanation, I assume the fan is also being powered by the laptop psu? (is that the "block" at the bottom of the light stand?)
What was the cost of components and how does that compare to a "standard" work light - of course the life span of the LED light would be considerably longer.

[Gerald D]

Alan, with producers trying to claim high power outputs, the lifespans of these new LED's are not that good.

[Alan_c]

So, no free lunch hey.

What is their lifespan to cost ratio? better than incandescent or CFL? We are all led to believe these LED's are the answer to lower power usage and longer life.

[Gerald D]

I don't see how a LED producer with a new "hi-power" product on the market can claim a lifespan of a longer period than what they have been on the market??

And then their fittings and "drives" are not standardised yet either.....buy today, and in a year's time they are obsolete??

Okay, I am a sceptic regarding this dramatic change. The CFL only just started to make economical sense in the last few years. And now we are expected to join the new hype. The few LED's that I have used, I have de-rated the power input to make sure that I get longer life. The poor producers are forced to claim high power ratings otherwise they won't sell anything.

[Surfcnc]

Hi Alan and Gerald

What you buy today is obsolete before it arrives, so never pay too much for a "high tech" LED product.
Gerald's point on overrating is correct, as always beware the headline specs and the suggestion on underrating is a wise one.

To put it in perspective all 3 10W LEDs were 27.48 AUD incl delivery.
5 x 5 watt resistors were 3.60 AUD, making the electronics all up around 31 AUD.
To complete the light a 12 volt laptop PSU, some alloy for the body, some epoxy and thermal grease mixed together to bond the LED to the alloy, a $2 60mm fan and connectors are required.
All a bit MacGyuverish, but it allowed me to experiment with the technology.

An Update

This evening I tapped some threads into a 40x40 SHS to swing my control boxes upwards from the side of the machine.
I have found three heavy Stanley gate hinges that should take the load to hold the boxes out horizontally for servicing.
Will send a pic once some more is done.

Regards
Ross

[Surfcnc]

Hi all

My design for the control boxes is now largely done.
The idea is to have the boxes swing up to a comfortable height of around 900mm for servicing.

First picture is the 15mm HDPE backboard, the stainless Stanley gate hinges and the 40x40 SHS the assembley swings from.
The 15mm standoffs provide an internal channel to route the cables back up towards the hinge.
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Second pic is the control box being fitted.
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Third pic the VFD box goes on.
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Fourth pic is the boxes swung down again for normal operation.
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I still have to work out the cabling fine details and to put in a few more standoffs to ensure the internal routed cables do not rub on any exposed bolt heads.
My original thoughts of gas struts have been shelved as the workbench and a block of timber will work just fine to hold it up for the initial wire up and any infrequent subsequent servicing.
The cables will come out of the bottom of the boxes and so I have allowed some extra sheet overhang to protect them as they do their U turn back up to the hinge.
The final thing I need to make it all work well is a block of something to absorb any vibration and fix the bottom of the swing away to the machine.
The 40x40 will be painted black and the ends capped with some knock in plastic inserts.

Cheers Gerald, I took that "lying on the floor fault finding" comment you made on the forum to heart and this was my solution.

Regards
Ross

[smreish]

....heck of an ingenious way of mounting. Each build, something new and innovative - just enough.

[KenC]

Ross,
Our penal is mounted almost identical position but your hinge is ingenious!! Love it! (mine is on a piece of scrap plywood which I bolt on the cross braces).
I'm in the process of adding a belt reduction box & after some measurement I realise the control penal is in the way.

[Surfcnc]

Hi Ken

Are you referring to my control boxes or yours?

I have had a look at how the belt drives hang and by my calculation my design was clear of the belt drives.
If clearance is an issue then the belt drive can be modified so that center of the larger pulley for the 4:1 reductions is moved upwards from horizontal to the center of the stepper shaft, this will retain near existing clearances.

Regards
Ross