DIY CNC Build

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EV2Go
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DIY CNC Build

Post by EV2Go » Tue, 16 Sep 2014, 02:11

Adverse Effects wrote: what are you going to do about the rest of the bed if the sides bow even 1 or 2 mm the center will sag 10's of mm just under its own mass then you will have the trouble of any thing you put on there will push it down as well

the bigger you go on the X and Y axis the harder it will be to level and keep level the bed

honestly i would love a mill 1.5 x 1 Mt but it would be a night mare to level and keep level with out going with a slab of 1 inch Ali and adjustable cross bracing in all directions

plus its better for me to play devils advocate now in the planing stages then you finding something bad out once its all built


You would be surprised how strong the 30 x 150 bed is. Even with me pushing reasonably hard in the middle of a single length of beam supported at both ends there is barely any deflection, add 16mm of solid base (4mm alloy 12mm ply) bolted to that (so it now acts as one structure) and bolt that to a steel tube base and it wont sink.

Remember the only thing pushing down is a couple of mm cutting bit. I am not concerned in that direction I am more worried about diagonal twisting when moving. Hopefully boxing in the ends so it becomes a square box and the top and bottom are supported it might be ok.

As I say my design is so much stronger than the typical flat bed with a separate gantry which doesn't add any additional support.

I am glad you are questioning what I am doing it makes me think twice before doing anything and its better to be safer than sorry.

Last edited by EV2Go on Mon, 15 Sep 2014, 16:13, edited 1 time in total.

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EV2Go
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Post by EV2Go » Tue, 16 Sep 2014, 02:16

Adverse Effects wrote: <a href="http://www.ebay.com.au/itm/Rapid-Check- ... 255df623bf" rel="nofollow">now there is a way to keep the table flat</a>


Yep I reckon that will do it :D not sure I will be able to lift that with more sore shoulder though.

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EV2Go
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Post by EV2Go » Sat, 01 Nov 2014, 19:53

Just a quick update... Severe slackness and poor bolt supply has prevent progress, but have finally started attaching the 30mm x 150mm alloy extrusion to the 4mm alloy deck.

Trying to get bolt holes drilled in the exact right spot to prevent a gap between the pieces has been quite tricky and despite some careful measuring, I am still needing to do a bit of hole slotting.

The 4mm alloy plate appears to be bowing in the middle as I attach more pieces of extrusion to it (had a slight bow to start with) so I am thinking I might just flip it over to see if it pulls them out the other way.

Failing that I might just put the 12mm marine ply directly under the extrusion and put the 4mm alloy plate below the ply instead of on top it.

Couple of mock up pics and first couple of lengths of extrusion bolted down.

ImageImageImageImageImage

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Adverse Effects
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Post by Adverse Effects » Sat, 01 Nov 2014, 22:11

mate for anything bolt related i have never been able to stump thes guys

Bolts & Industrial Supplies at
5 Project Street,
Salisbury QLD 4107,
Australia.

as for the flex Image i did warn you Image

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EV2Go
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Post by EV2Go » Mon, 03 Nov 2014, 17:17

When buying in quantity it is unfortunately too dear to buy in Australia. I can buy T bolts in China for a few cents each whereas the probably want like a $1 each here :(

So even though the postage is on the expensive side if you negotiate shipping it can still work out a LOT cheaper. Unfortunately there was an issue in HK when I tried shipping mine combined with a slack shipper.

In hind sight I may have approached the holes from the wrong direction. Because the alloy is the meat in the sandwich I tried to drill them first and was just going to place the alloy plate on top and drill through the ply.

I don't think I factored in the thinness of the plate enough. So tossing up starting again but this time drilling the holes in the ply first.

I may be able to use the holes I have already drilled in the plate as a template.

Image

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Post by EV2Go » Tue, 04 Nov 2014, 00:21

Two tricks I have learned from YouTube.

The first is if you want to drill numerous holes and you need them to be as accurate as you can get them, then start with a reasonably thick piece of wood and drill through it as straight as you can with the bit you want to use. I used my drill press but it was still a poofteenth off square. The holes do tend to flog out the more you drill with them so I wound up getting through three holes.

The second trick I picked up is to use drill bits the same size as the holes you want to drill as material locators. I tired where possible to also use the hole in the scrap board for location.

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I learned while trying to use my first attempt at drilling holes in the alloy as a template. The key take away from this was your first and last locating holes need to be perfectly lined up. Mine was out a tiny bit which meant I sometimes had to use the second row of holes.

Image

All holes finally drilled. The first couple of rows I kept trial fitting the extrusion. This was very time consuming taking the bolts in and out. After the first couple I finally decided I would just chance using template and slot any holes that needed fixing up later. Very surprisingly the holes all line up really well and there was virtually no gap between the extruded pieces.

Image

With the aid of my lovely assistant we bolted all the extrusions onto the ply.

ImageImageImage

Hmmm seem to have about a 1-1.5mm bow in the ply... Lovely assistant holding piece of spare shelfing where some solid 50mm square heavy wall tubing might need to go.

Image

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Adverse Effects
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Post by Adverse Effects » Tue, 04 Nov 2014, 03:53

thats a lot of holes

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EV2Go
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Post by EV2Go » Tue, 04 Nov 2014, 17:15

125 bolts. I wanted to secure it to pull the deck flat, but wondering if it didn't have the opposite effect.

Think the only way I am going to get it properly flat is to build a big steel frame around the outside with some bracing in the middle and bolt the extrusion to the frame.

Was always planning on doing that but was hoping to do it down the track.

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Post by EV2Go » Fri, 07 Nov 2014, 22:13

Ok third time luck (or is it only second since the alloy and ply were meant to be together as the deck support).

I had always planned to bolt it all down to a steel frame for rigidity but now that I have measured the ply a little better than a guestimate, and I see a ~4mm bow in the board end to end from tension I am giving second thoughts to using the alloy and ply under the extruded deck.

I may just bolt the extruded alloy directly to the steel frame and not use the alloy plate or ply, or I just might use one of them instead of both.

I was thinking it would be good to have some kind of board underneath in case machining liquid found its way in-between the extrusion but I could probably just as easily put some plastic sheet under the deck to catch any soluble oil.

Went down to the steel shop and was all ready to get two 6m length of steel cut up only to find out they were 8m lengths not 6m :(

So I had to do a few quick calculations on the fly. I decided to get six pieces cut at 1.65m (15cm longer than needed to put tools down) and 2 x 1m pieces for the end. I got them to leave the ~2m offcuts in longer lengths as I was unsure what I was going to use it for.

I will probably use the other bits towards the legs or bracing for the frame. I wound up getting 4mm thick 35mm x 65mm. Again not knowing what they stocked I had to make a quick guess at the most appropriate size.

Image

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Adverse Effects
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Post by Adverse Effects » Sat, 08 Nov 2014, 02:02

well just let me know if you want to come around and use some tools

dropsaw
welder (mig gassless)
7foot bandsaw
and on and on

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EV2Go
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Post by EV2Go » Sat, 08 Nov 2014, 05:03

I really could use a hand if you're up for it.
Last edited by EV2Go on Fri, 07 Nov 2014, 18:03, edited 1 time in total.

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Post by Adverse Effects » Sat, 08 Nov 2014, 06:19

at the moment i only have Monday morning booked

Last edited by Adverse Effects on Mon, 27 Apr 2015, 07:45, edited 1 time in total.

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Post by EV2Go » Sat, 08 Nov 2014, 14:57

Thanks Ivan, I'm not working at the moment (having a year off) so whenever is good for me. How about you PM me your address and a date / time that is good for you. I'll start putting a frame design together.

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Post by EV2Go » Mon, 10 Nov 2014, 02:46

With Ivan's help we made a start on the tube frame. It took longer than I expected it would, but there were lots of measurements and a few small tweaks in-between welds to make sure it was as square as possible.

I managed to squash a finger and get some ray burn in the process, but considering I haven't MIG welded in at least 20 years I thought I did ok.

Not great welds but not crap either, so happy with the result.

ImageImageImage

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Post by Adverse Effects » Mon, 10 Nov 2014, 02:56

hehe its not as easy to keep it from twisting is it lol

we even had to re do some welds over the top of the welds ther where there to try to shrink the frame in shape i think about 1mm corner to corner and about the same in twist is darn good

its funny thos pics realy dont show that that frame is over 20Kg isnt it as it sits?
Last edited by Adverse Effects on Sun, 09 Nov 2014, 15:57, edited 1 time in total.

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Post by EV2Go » Mon, 10 Nov 2014, 03:32

If we wind up using both of the 8mm lengths it will be around 90kgs before aluminium extrusion, which will add another 50+ kgs.

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Post by EV2Go » Tue, 18 Nov 2014, 02:04

Despite the heat some progress is being made on the new CNC table frame. It's taking me much longer than I expected to get the welding / weld prep / grinding work done.

Ivan and I are trying to do it right first time, so we don't have to spend time later on trying to fix up mistakes. While I have done some welding a long time ago, Ivan's welding experience and tips on metal distortion are helping me get the most out of my limited experience.

This afternoon we sat around chewing the fat on how to best attach the legs and to get the best out of making it portable, with a view to permanent mounting. Decided will finish off all the welding first and turn it right way up and prop it up on some temporary supports and see where inspiration takes us.

Image

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Post by Adverse Effects » Tue, 18 Nov 2014, 02:17

just so others know that is upside down the way its sitting there

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Post by EV2Go » Sun, 23 Nov 2014, 20:39

Finally after what seems like forever I managed to finish welding the four corner posts into position. Before calling it quits for the day I tacked on the (top in picture, but actually the bottom) four rails into place.

Using Ivan's ultra sophisticated calibrated precision measuring device (that would be the plastic clamps with the alloy tubing) we checked to make sure the top and bottom rails where parallel.

We did a quick measure after all the tack welds were done and it was perfectly square corner to corner. Fingers crossed I am hoping it stays that way after final welding is finished.

Several times now I have wanted to take a few shortcuts to speed things up but Ivan is keeping me honest by casting an eye over every step. :D

ImageImage
Last edited by EV2Go on Sun, 23 Nov 2014, 09:41, edited 1 time in total.

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Post by Adverse Effects » Sun, 23 Nov 2014, 21:22

start with a good base unit end up with a good finished item :-)

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EV2Go
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Post by EV2Go » Sat, 06 Dec 2014, 00:11

Disassembled the old frame and top I was planning to use and had a clean up to make way for the new CNC frame.

Bought some 75mm square (2.5mm wall) and some 25mm square (1.6mm wall) today for the legs, top rails where the X axis will go, and some bracing.

ImageImage

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Post by EV2Go » Sat, 06 Dec 2014, 22:21

Didn't get anything done today but we tossed around quite a few ideas. We have unanimously decided to go back to one of my previous ideas that I didn't think much of the time, but with a change of bar size it now makes more sense.

This mock up should look something like the finished product.

Image

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Post by EV2Go » Tue, 30 Dec 2014, 19:02

After what seems like an eternity I finally have the frame home. Now the million dollar question is how to get it in the shed.

Special thanks to Ivan for all his advice and ensuring that it turned out as well as it did.


ImageImage
Last edited by EV2Go on Tue, 30 Dec 2014, 08:03, edited 1 time in total.

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Post by Adverse Effects » Tue, 30 Dec 2014, 19:17

i have 1 thing to say

THAT B$#H is heavy OMG

LOL

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Post by EV2Go » Tue, 30 Dec 2014, 20:28

Yep a fairly accurate guess would be about 150kgs in the frame alone (deck takes it over 200kgs). BTW Ivan I got it off the ute by myself :D

And yes it fits, only just but it is in there... Time for a beer.

Image
Last edited by EV2Go on Tue, 30 Dec 2014, 09:29, edited 1 time in total.

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