Hi everyone

Well another nut joins the fray. Today I bought the steel I need to start my machine and starting this week I will start assembly. I figured I had better start a log now so that I can get the community to make sure I finish it! I am pretty good at the first 90% but always slack off near the end.
Anyway here goes.

The machine has the following specs / design features:

Gantry 3 axis plus rotary chuck on table
Configurable to become a 4 axis hot wire
3 table heights
Max working envelope 1.4m x 2.6m x 0.5m
Z drive - rotating ball nut 1:1 belt drive 16mm lead 450 oz/in stepper
X drive (across gantry) - direct driven 16mm lead ball screw 450 oz/in stepper
Y drives (2 independent) - 8:1 belt drive to stationary T5 belt each side in Omega drive config 450 oz/in steppers each side
Frame bolted steel 75mm sq tube and 150 x 75 I beam
Gantry 80mm sq 8020 aluminium extrusion (Item)
Bed / vacuum plenum - 8020 frame with 19mm forming plywood skins each side
Pneumatic counter balance on Z axis
Pneumatic raising and lowering of working bed (pinned in working config)
Epoxy grout used to level I beams prior to Y axis rails installed
Vibration mount feet on bed an fran used to rough level machine
Possibly fill frame legs with sand to increase dampening.
Current chop micro stepping drives

The design is intended to be open enough to allow the machine to be reconfigured to do jobs of varying needs ie.
in the high bed setup it is ideal for sheet work up to 150mm
Mid brings the bed mounted rotary chuck into line with the gantry for small detailed 4 axis work or thicker sheet work
Low position gives maximum working envelope and ability to spin columns up to 500mm in diameter
By being able to decouple the independent Y drives from the gantry this allows two new Z axis to be added to each Y and form a 4 axis hot wire machine with the maximum working envelope.

The design was also limited or built around existing parts that I was able to get for free from some decomissioned printing gear hear at work. the sad thing was I did not get everything and it all went to Simms metals and a crusher :( THK bearings, linear and rotary stages etc etc. The good news is I save enough to build one machine :)
So if you are looking at the design and woundering why I used big bits of billet aluminium here or that ball screw there the answer is that I had it.

So far it only really exists in CAD but hopefully I'll be able to post some real pics real soon. All comments suggestions or problems anyone sees please feel free to chime in.

Here's one idea that maybe someone can comment on:
As stated the frame is a bolted affair as I need to be able to dismantle the beast if I want to move it out of the garage and to a proper workshop if I get any work for it. Given my total lack of machining tools I intend to forgo all the nice pin arangements like on MadVac's machine and instead decided that the only critical part is the last surface the rails sit on. So heres the idea. Build the frame and level as best as possible with the vibration feet then form up the top of each of the I beams and have a connecting channel between them. Pour some very low viscosity epoxy grout into the formed area and let gravity and time to the rest. This hopefully will give me a perfectly level and coincident plane on each I beam onto which the 8020 extrusion and THK rails can sit.

BTW not all details are shown yet on the CAD drawings

Here goes nothing.... other than any spare time or cash I had :P

Cheers

Mark

BTW I live on the Central Coast of NSW any one else local?

Whoops

Great start I spelt build wrong:rolleyes:

Looks like you are off to a great start... I am in to see how it all goes :)

Russell.

Firstly its great to see another Aussie. But i dont think this is just 'another build' this machine sounds like a dream to most of us. Huge and well thought out. I really look forward to following your build? how long you estimating the build to take? Really good idea to do a timeline just to push you that little furthur with staying on task. lol.

Daniel
P.S Im on the South Coast, would have been great to be close and watch your build and the finished machine in action.

Hi Mark,

Looks like it is going to be pretty good :) I will wait until you start sticking metal together before commenting further.

Good start.

Cheers,
Bob

Thanks guys

I havent put a timeline as such on it other than this year as I have been wrong too many times so far and I have a couple of jobs waiting on it so I don't want them to get over confident on a delivery date. Under promise and over deliver was always my motto as a field tech. If you promise to do nothing then everything you do is a great achievement :)

I checked out your profile Daniel. We head down to Jervis every year at Xmas for some camping and sailing... you live in a great spot.

Hopefully the "dream machine" doesn't turn into a nightmare. My biggest concerns at this point is whether the steppers I have will be grunty enough (not a huge drama as the drives I have can accomodate up to 8 Amps) and how well the belt drive will work. The cost for dual rack and pinions or dual ball screws at this scale made me discount them for now.

I'll see if I can't take some happy snaps of the pile of bits this week and hopefully a start at the frame.

Cheers

Mark

I'm still looking for my camera but progress is being made. All the steel for the base is cut and my son is half way thru what needs welding (handy having a apprentice boiler maker in the family )

Must say the resource boom is evident when you look at the price of steel !

The "Z" on its side of the legs will be welded together to make 4 sub assemblies these are then bolted to the I beam (studs welded to the inside of the legs)


So here's a few more CAD drawings with a bit more detail showing the omega y belt drive with trhe reduction and idlers (without the belts shown).

The extended leg of the side plate on the gantry pic is what attatches it to the Y drives.

Also a closeup of the Z axis driven ball nut.

Need to find the camera so I can post real as opposed to virtual progress

Cheers

Mark

Hi Guys

Couple of pics to prove that this thing is starting to take shape outside of CAD.

First off the obligatory messy garage shot. :) Hopefully over the comming weeks this pile of stuff will start to resemble the drawings.The 8020 framework for the movable bed is standing up on the right.

Pic of the legs with the studs welded to the top.

The last pic shows how the Y rails are a composite construction of an 150 x 75 mm I beams for support with a 80 x 40 Al extrusion (8020 / Item ) and finally the THK bearing rail on top. They are held together by T nuts so they is some slack in mounting to allow for alignment. As stated earlier I intend to create a shim layer between the I beam and the 8020 by pouring a layer of slow setting epoxy and letting it set off hopefully to a level smooth and coplaner surface on each I beam.

Cheers

Mark

like the 3 stage table height, I too was toy with the idea to, like to see more details how you plan to lift it, and your railing system for it to side up and down on. what did you to cad it up in solid edge?

Ok

Its sunny
I have a camera
and I couldn't resist....


Now where did I put all them bolts :)

BTW the real Z axis is not that long.

The design philosophy I'm working under is that it needs to be tolerance tolerant. What I mean is that as all the errors of machining in a assembly (which are quite large tolerances given my lack of machine tools / mill etc) are accumulative and either you try and reduce these to a very small amount or, (as I'm doing), accept them and allow for adjustment in the design to correct them in the critical parts. The critical parts in a 3 axis router IMO are the rails and the axial runout of the spindle.... nothing else. These need to be securely held (to maintaine tolerance) in relation to each other. Thats the theory... now lets see if it works in practice.


Cheers
Mark

Hi Eloid

I'm using Solidworks.

The table will be lifted by two large air rams I'll post a more detailed pic when I get home. Basically the table has 4 Thomson ball slides mounted to it near the 4 inner legs of the frame. The rails mount on these legs and on the other side of two of them (diagonally opposed) are the air rams. This is the setup that was used in the vacuum frame in the original plate making exposer that they were "saved" from. The idea is that I will lift the table then pin stops below it then allow the table to come down to rest on these stops.

The rails are mounted on angle extrusion with adjustment slots to allow for setting them up parallel etc and will be bolted to the sides of the legs which have tapped holes in them.

I plane on using the same style of air ram as a counter balance for the Z axis.

I hope to be able to level the table out easily at each set height.


Hopefully I'll have some real pics by next week that show this stuff in better detail and "in the flesh".

I would love to get input on my Y axis drive idea as these bits cost money and want to be confident of success.

The AT5 x 25 belt will be held stationary and under tension. It also will lay in a grooved support for its entire length. The belt is lifted outr of this groove around a large smooth idler pulley on the Y drive carriage, around 180 degrees a 15 tooth pulley the laid back down on the support by a second idler. The 15 tooth pulley is driven through a 3:1 belt drive by the stepper motor.
This arrangement should mean that 1 rev of the motor will result in 25mm travel ( 1 rev of 15 tooth AT5 pulley = 75mm, 3:1 = 1 rev of motor = 25mm) devide this by 200 and I have a resolution of 0.125mm per step or 0.0625mm per half step.
I will be using micro stepping however I only consider half step as being considered as a reliable resolution figure.

Accuracy however is going to depend on a lot of factors and at this stage I think only building it will show how good or bad that will end up.

The grooved belt support has two purposes:
stop the belt getting any bounce
help with tracking

I'm hoping that this will form a rack and pinion style drive with better tooth engagement as the belt (flexible rack) wraps the toothed pulley (pinion).

Cheers

Mark

Hi guys

Here are a couple more pics to show that progress is being made. I was able to use the mill at work to make my Z-axis plate.... AKA swiss cheese. With 4 bearings for the Z and 4 on the back for the X plus all the mounting holes for the Z axis motor and X axis ball nut it took me quite a while to get them all done. The large hole you can see is something that was pre existing in chunk of ally I'm scrounged

I am planning a fairly ambitious dust guard for the X axis ball screw which consists of a flexible sheet that is fixed to the gantry and is diverted around the ball nut by 4 rollers similar to what is used in air cylinders that have side access to the piston. The back of the flexible sheet has two rows of foam tape that are forced into the grooves of the 8020 extrusion and form a seal. Bit hard to make out in the pics but it works in CAD so how hard will it to make in real :rolleyes:

I also did all the mounting holes for the bearing rails in the U channel Z axis.

Prep'd and undercoated the steel base and will have the last bits welded by my son this weekend so should have nice pic of it built and in its final yellow paint job soon. :)


Cheers

Mark

Opps lost the attachment. Then the zone died with database errors....hope that wasn't me!....lets try again

Hi Mark,

Looking good now :) lucky having the mill at work too!

You will be flying before you know it :)

Bob

Well its together and is happily quite rigid even without any gussets which may be added later.
Heres a couple of pics to show virtual versus actual. Boy I need to tidy up a bit as I now have a lot less room to make a mess ;)

Next step is to pour the epoxy shims for the 8020 extusion mounting. I have used vibration feet for now under the fram but may decide to dynabolt it to the floor instead to give it true rigidety (sp?) as although it is already quite heavy without all the rest of the machine on top it can be slid around quite easily (not a desirable attribute)

Onward and upward.

Cheers

Mark

Here's a better pic of the table lifting gear Eloid.

The two cylinders have 16" of travel and are made by Hoerbiger/Origa
Type 2020/25 bore 40

The four bearing rails are Thomson TWN 16 OPN.

I still have to make all the plates and brackets that tie all this together and to the actual cutting table.

Like stated earlier the air rams are there to lift but not support the table and allow it to be pinned in 3 locations, high,low and mid.


Cheers

Mark

Hi All

Well here goes nothing (except 3 odd liters of epoxy). I formed up the I beams with 25mm aluminium angle, double sided tape, packing tape and blue tack. Threw in a few clamps to be sure.
I got a few bubbles in the mix but they should not be too much of a deal and easily cleaned up once the slow setting (expect it to take at least 24hrs at the current temp) epoxy goes off.

I should be able to tell with an engineers level if it was worth the effort in a couple of days.

Here are a few happy snaps showing the depth of the epoxy (about 5mm) and the cross over bridge to allow flow from one side to the other to get a common level.

I decided to just use the west system epoxy I am used to using for fiberglass work instead of something more exotic like epoxy grout or liquid steel. I figure this stuff should be more that hard enough to act as a wide shim beneath the 8020 extrusion. Time again will tell. If this works then the rails will be mounted this week and I'll have a moveable gantry ready for me to finish the belt drives.

cheers

Mark

PS sorry for the poor quality of the pics as its a bit dark in my garage.

Hi all

Well it worked...sort of. I'm fairly happy with the results which, while not perfect, are an improvement on the previous level of the I beams.

The next time I do this I would make these changes:

Try and find a lower visciosity epoxy like which is used in vacuum infusion.
Remove air bubbles by puting mixed epoxy in a vacuum chamber.
Pour the epoxy more equally around the mold rather than allowing it to just flow around.

After removing the Aluminium angle mold I used a file to get the worst of the meniscus lip off then followed up with a large flat piece of aluminium plate as a sanding block. I just kept an eye on the shiny central surface of the epoxy and sanded until the edges met the middle.

It looks cool too having the 8020 suspended 5mm above the I beam on clear epoxy (never discount the cool factor :) )

Due to the unsuported nature of the I beams in the center in my design they can flex sideways to correct minor twisting of the top surface anyway.

Heres a few more pics anyway

Cheers

Mark

Hi all (assuming anyone else is in here... feel like I'm talking to myself sometimes)

Well I bolted the 8020 (Item) extrusions to the I beams and the THK rails on top. With everything snugged down the gantry runs nice and smoothly back and forth with minimal effort. The Z axis on the otherhand is a bit stiff for my liking and I'll need to figure out why that is.

Even without all the bolts and side plates installed on the Gantry it is very stiff and resists skewing so its all looking good so far.

There is a fair bit of work to be done to make the Y axis drives and I'm waiting on a new boring tool to show up at work before i do that. I am only using the mill for critical parts this as I hate driving 1 hour on my days off to come to work. It is handy though as I need to make sure the drive is all square to stop any issues with the drive belts "walking off" the idlers. Geez I hope the belt drive idea works!

If I havent said it before I have to thank all the various contributors to this group for the inspiration and ideas which I've thrown into my build.

So far my motivation has been a small porche (demo of V-carve if I remember right) that I made on a small test bed I slapped together using 3 Deadal linear stages. Its what got me going and convinced me that I should buy Mach3 and start this journey.
The department I work in is called Computers and Comms or C&C for short. I've always written that CnC and thats what I wrote on my little carving "The Real CnC department" :) Most of the computer geeks didn't get it.


As others have said its pretty awe inspiring the first time you see your build cut a 3d object out of a solid bit of timber. It was also a bit scary when it tried too hard and too fast :( . That was on the baby 4"x"4"x3" machine I can only imaging how terrifying my big beast will be if it gets out of hand! I plan on having several E stops around the machine just in case.

Cheers
Mark

Hi all (assuming anyone else is in here... feel like I'm talking to myself sometimes)


You're not talking to yourself... keep up the good work !!! It is looking pretty awesome so far !

Cheers.

Russell.

I'm reading too. :)

And my to.

Bubbles, couldn't you apply a little heat and they come to the top and disappear. At least they did back in the 70's, all you had to do was warm it with your breath the they would go away. This might require a hair dryer.

Ok

Its sunny
I have a camera
and I couldn't resist....


Now where did I put all them bolts :)

BTW the real Z axis is not that long.

The design philosophy I'm working under is that it needs to be tolerance tolerant. What I mean is that as all the errors of machining in a assembly (which are quite large tolerances given my lack of machine tools / mill etc) are accumulative and either you try and reduce these to a very small amount or, (as I'm doing), accept them and allow for adjustment in the design to correct them in the critical parts. The critical parts in a 3 axis router IMO are the rails and the axial runout of the spindle.... nothing else. These need to be securely held (to maintaine tolerance) in relation to each other. Thats the theory... now lets see if it works in practice.


Cheers
Mark
Hi Mark.
Looking good where did you get your cable chain from?I need something similar but a bit smaller for my build which is almost complete.I'm in Penshurst (St.George area)

Eric

Hi Guys thanks for the interest. Please don't be shy about passing comments or questions on the design especially critical ones. Praise is nice but constructive criticism is better.

These forums are often like walking into a large dark room only to find out you are not alone.

I tried a bit of heat using a heat gun but I was too concerned it would set off the epoxy to soon before it had found a nice equilibrium. It was pushing the epoxy around without really bursting the bubbles . I've read elsewhere that those doing vacuum infusion of resin often will put the mixed epoxy into a container and evacuate it to release the bubles prior to infusing. In the end they were not that big of a deal.

Erkiwi (BTW I'm half Cunnuck, half Kiwi) 99% of my machine is salvaged gear from work including the Nylatube brand cable chain. I've been extremely lucky in that so far the only thing that Ive actually had to buy is about $500 of steel for the frame and $350 for all the Item extrusion. Its going to make some cry but they sold it for scrap value per kilo.
I salvaged what I could including THK bearing blocks and Slosyn stepper drives, Daedal linear and rotary stages and once the machine is built I may be able to pass on some extra bits to locals if I don't need it. For now I'm being selfish as I have not yet finalised all the design details and I want to have a few spares. I am not a selfish bugger by nature and I already made a couple of local home boat builders/designers really happy by donating a couple of Gast vacuum pumps.

The design has been driven by both what I would like the machine to be capable of doing and the parts that I have available. Thats how an originally MDF small machine evolved into the beast you now see. Bits that are off spec are the HTD5 belts and a longer 1.5m (I only have 1 m length from the scrap) THK 1616 ball screw for the Y (gantry) axis. As these are quite large ticket items once you include the machining and pulleys etc I am the most nervous about their design and implimentation.

BTW I think I've been mixing up my X's and Y's. so from now on I'll use Rainea's definition :
http://www.rainnea.com/cnc_support.htm


Tonights my last night shift so I'll be able to make a bit more progress over the weekend. I'll post pics as I know I understand stuff a lot better visually than a word description.

Cheers

Mark

Good work so far Mark.
I'm in for the sticky beak too.

wel done Mark...keep up posting.
cheers

Hi guys

The stiff Z axis turned out to be two things... one I had sort of expected and one that raises a dilema.
The obvious one was that I was hoping the back of the aluminuim U channel I am using as the Z axis slide would be flat enough without machining and if it weren't the fairly thin web would twist to the will of the bearings... Thats a big no on both accounts. As I don't want to flycut this piece (not a lot of material to begin with) it looks like another job for an epoxy shim. I could go out and buy some Devcon liquid steel but its a bit pricey so I think I'll try my straight epoxy again.

The second culprit was the dust seals on the bearings themselves. I guess they must have swollen or something as it makes them very stiff and I think I may run without them. As these rails are vertical and I can put in a dust brush to stop the worst of any flying bits of wood. I think it should be OK.

Heres a pic of the small CNC I threw together to do the proof of concept and test some of the softwares like Mach. Its pretty rough and I didn't line anything up. the small car I cut was held down with doublesided tape...yep it moved. But it still looks like a car :)
The axis are Deadal linear stages. Two 6" ones stacked on top of each other under the white block (I made a sliding dust plate on top out of formica I had lieing around.. its actually made up of 4 pieces) and a 4" one for the Z which has my small trimmer router held on with hose clamps.

The big one has had a lot more thought put into it.

Cheers

Mark

Looking good where did you get your cable chain from?I need something similar but a bit smaller for my build which is almost complete.I'm in Penshurst (St.George area)

Eric
.

I have a source for cable chain if you're still looking. In Melbourne.

http://www.insul-8.com.au/

Here is a temp link to a PDF which I found somewhere of the brand details

http://web.aanet.com.au/greolt/cable%20chain.pdf

Greg

Hi Guys

Been a bit slow the last few weeks and my camera decided to intemitantly die. Anyway I got it going again so here's a couple of pics.

I finally am doing the epoxy pour for the Z axis. I should really use some liquid steel for this one as the compressive forces are much more localised than on the side rails under the 8020 extrusion. What i may do is use a end mill or forester bit to make counterbores into the epoxy around the threaded holes then fill these with liquid steel or steel putty to form compession spacers while leaving the rest of the plate. The cheaper west system epoxy thus forms the top referance surface and the mold for the harder epoxy steel. (Sounds good in theory)


I also have a bit of a hickup in the design. Reading other posts I stumbled onto a discussion on THK bearing rails and there different profiles. I hade never really looked at the specs for my SR rails and assumed they would be fine for the Y axis on the gantry mounted on the vertical surface. EEEH! wrong!.. Luck for me they are talking about chucking another bit of kit and it has some nice Origa roller bearing rails which should do the job nicely :) Problem is they have a different mounting pattern so my nice bit of swiss cheese Z bearing plate will have to be redone :( Ah well practice makes perfect.

I put a couple of pics of the electrical box (painted black so I dont see the smoke escape) and the drives and power supply laid out. The kit that the Slosyn drives was taken from used this 48vDC switching power supply for the motors, yet I've read elsewhere that a linear PS is recommended... Anyone know why?

I really need to make a concentrated effort to advance this build as I get bogged down in the details to easily. I'm getting ahead of myself also as I ordered a smooth stepper and it will be here this week.... I really want t o play with it but haven't done the belt drives for the beast yet... I'll have a play with the small prototype instead.

I read all the posts and watch the videos of all the cool stuff everyone is doing with their machines and I tend to day dream instead of getting on with the job of joining you lot.

Better sign off and do some work huh?

Cheers

Mark

Hi Mark,

Looks better now, you will get there :)

Cheers,
Bob

Thanks Bob

When I do finally get her running I'll have to put my first cut to the music. I was thinking of re dubbing an old Hollies song ...... "She ain't heavy. She's my baby..."

Well she is a bit heavy but that would be rude to point out :)

BTW I love the Lithophane you did.... on my list of to do items once the chips start to fly.


Have fun at the BBQ

Cheers

Mark

That would not be bad, I'm a bit partial to the Hollies :)

There is another litho and video on my build log :) getting the things down pat now :)

BBQ is going to be good, huge amount of CNC'ers coming!

do you have any plans to release your wing schematic?
It always nice to see how every handles there estops / limit switchs and wiring for there drives.

Hi Markus

Had to read this 4 times before I figured you meant wiring. I haven't drawn a schematic as yet but will get around to it one day just for future trouble shooting.

Basically I have a Opto22 brand optical isolation board and intend to use a smooth stepper board to interface to the computer.

The drives (slosyn md2000 if I remember properly) already have internal opto isolation so these will be directly driven by the SS board where as all the limit switches are 24 Vdc prox sensors (non contact) and will run thru the Opto 22 board. All signals are 24dc to drive the air solenoids and main power relays. Estop drops out this voltage on the mains and also will set a signal to the SS board. Note I intend on upgrading to Gecko drives after I get this up and running as the older Slosyn drives do not have harmonic dampening or all that other cool stuff the Geckos have.

The mains in will be fused as will the motor driver power.

Power / signal distribution will be via a Din rail terminal strip.

I may end up having a second electrical cabinet to separate the high power side from the control side as space is a bit cramped in the one box.

Still deciding on location for additional E-stops (there is one already on the electrical cabinet) or if over limit switches are all that is needed.

At one pint I was thinking of making a "smash bar" that ran down each side of the gantry so that one could hit this and it would activate an estop. The design is still in a state of flux on this point.

All pretty standard stuff really as far as wiring goes.

Cheers

Mark

Hi Guys

Well a wise man on here once said "if you get bogged down in you project... drill a hole". I'm starting to see the wisdom in this as yesterday I had to drill:

44 M6 clearance holes
88 M6 counterbored holes
and
132 M6 tapped holes

Took me a lot less time to draw them on CAD!

Another wise man once said "measure twice and cut once" so I had to redo 44 tapped holes :( I had overlooked a collision with another part and had to trim half of the stops.


All this was to make my adjustable stops for the table 3 position lock. I finally came up with an idea I am happy with to make this hopefully an easily adjustable and rigid locking setup for the table hieght as well as being easy to activate by a single user.

Here's what i've come up with:

Mounted to the table are 8 pneumatic "hinges" that line up with each of the frame legs. The Bimba cylinders are spring return so are in the normally locked position (hinge leg extended) and thus will rachet up over each on the 3 adjustable stops on each leg in the same way a door latch works. This way to raise the bed on needs to only raise the bed and stop once the locks have cleared the desired level.
To lower the the sequence is to first raise the table then activate the "hinge lock" air cylinders to retract them. The table is then lowered and the lock is released once the previous stop is passed.

As the "hinge" is applying an inward force directly to the floating bed this should effectively make the table be held very stiffly as the weight of the bed increases. Also with this design no force is exerted on the actuating cylinder at all and locking is not reliant on air pressure but rather on geometry and the spring return.

Lateral movement of the table is restricted by the 4 vertical bearing rails.

The stops are made in two pieces with the outside bolts pushing up to adjust the hieght of each stop and the central one just there to hold the two pieces together. The idea is to drill and tap the lower ones in first then adjust the table to level and then drill and tap the tops. This just saves me making sloted holes in the top parts.

Cheers

Mark

BTW I live on the Central Coast of NSW any one else local?

Hi Mark I ain't local but only about 3 hours I think? I am in Port Macquarie Just moved back From Brisbane after 10 years and will be starting my second build very soon I am hoping about half the size of yours.

I looking to build a fully sized table but don't have the room until we buy another house :( in the next 12 months or so.

I think your Idea on the pneumatics is excellent cant wait to see it in action may have to come down and have a look.

Just purchased a MIG to build some tables as I have nothing at the moment and need one for my Little CNC that Is sitting naked on the floor.

Sean

PS: what did the Item set you back if you don't mind me asking?

Lookin great Mark, keep the pics flowin!!

Hi Sean

You are going to hate me but the Item extrusion all up cost me $350 (some of the bigger stuff sells new for around $150/meter). There is about 280Kg worth of alloy there that work was just throwing out. I did a bit of a dumpster dive and salvaged it from going to Simms scrap metal. In fact most of my machine was either free or scrap value so that is why I'm making so big.

The whole project has evolved as more stuff is chucked out at work (we have been decomissioning a bit of gear recently)

How big of a machine are you designing?


Cheers

Mark

Well my camera finally bit the dust (canon S1 know fault that will get fixed free) so I've not got any pics just yet.

I've been making the table locks today and again it goes so much faster on CAD than in the real world (can't wait till I have a machine to do all the cutting and drilling for me :) ).

I should have made the pivots at work on the mill as I found that I didn't do a great job of making the shoulder bolt holes on each side exactly line up. :( Consequently I have a bit of bodge work to do on each mechanism to make it pivot freely...bugger.

Been doing a bit of research into what type of belt to use for my X axis.

Looks like the best profile is GT from Gates which is supposed to be much better than the AT or HTD I was originally looking at. Problem is I wanted 5mm pitch x 25mm wide and this appears to be made out of "unobtainium". located 30m spool in UK but cant see that as an option.

So not the idea is to use 8mm pitch which is easier to get and they even have a standard belt that I could cut to make each side instead of needing belt off a spool (harder to source).

Down side is the resolution and torque suffers as the minimum sprocket is 22 teeth

Rough calc with 10uSteps and 4:1 belt reduction still gives a respectable 0.022mm / 0.0009" per uStep this is still an order of magnitude greater than what I need so I'm still happy.

With the 16mm x 16mm lead ball screws I have the Z and Y will have 0.008mm / 0.0003" which is again heaps.

I'm delaying getting these bits as finances are a bit stretched right now and I still have lots of bits to build out of the material I already have.

Cheers

Mark

Hi Mark,

I wanted to build one close to the size of yours (a sheet shredder :rolleyes:) but due to only having a single garage at the moment that will have to wait as the wife wont let me keep the tools in the house for some reason.

So the machine I am designing at the moment will have a envelope of 1x.500 all up and should keep me busy for some time.

I will need to get a piece of Item for the Y axis would love to use it for the X but the $$ will probably kill me so I am working on another plan of attack it will be R&P for the drive and probably an actuator for the Z just have to see how it go's.

Sean

any new progress on you awsome cnc....

Hi Markus

Well its been a bit slow this past 2 months (geez I didn't realise its been that long!) and I still haven't fixed my camera so what little progress I have made I can't post pics right now.

So... Whats happened in the mean time. Well I've finished all the table locks and done a test assemble of the bed and they work great so far. I still have to route all the pneumatics to actuate the table and I should get on that this week. I'm a little concerned that I won't have enought lifting power once the ply bed is on plus the work piece but it should be close. All up its looking like it will weigh just shy of 300lb for the table alone!

Had a bit of a win as I see someone is making a linear drive like I was thinking and it appears to work really well so my concern over my design has lessened. Check it out especially the video. http://www.cnczone.com/forums/showthread.php?t=59570
very cool!

Also started on adding a second electrical box as I've decided to mount the pc an all low voltage signal stuff in one box and all the high power drivers, peumatic solenoids and power supplys in the other. Less cramped and better noise immunity.

Thanks for the prod to get a move on as i've been a bit slack!

Cheers
Mark