Tiddy CNC.

[TonyD]

Next Steps.

Hello all. I've made some progress lately. The control system is nearly finished (bar some limit & home switch mounting), and tested on The Z Axis which is just about there. The Y is nearly there, just need to mount the stepper which leads me to the frame. I have looked at many frame's and tried to come up with my own. There were three features I was looking for

i) I wanted the frame to be robust enough to support cutting aluminium
ii) I wanted to be extend the rails over one end for over sized jobs (thanks jazz)
iii) Thinking of the over size issue, I wanted the frame to be tall enough that I could mill out the lock on a door.

The machine will be inside so I'm looking for welded frame sides with bolted cross members. I also decided I didnt want the hassle of a moveable bed, frankly I want to get the thing built (this year), so left 110mm of Z travel from the tip of the spindle, I think thats enough for general use? I also decided at this stage to have two rails (in orange) welded to the sides as support for the drop-in welded bed frame (purple). With the exception of the top rails, everything else is 50x50x3. I havent costed it yet, will probabily have to revise on that basis alone but wondered if there was any feedback on the design so far. Thanks.

[Boyan Silyavski]

Next Steps.

Hello all. I've made some progress lately. The control system is nearly finished (bar some limit & home switch mounting), and tested on The Z Axis which is just about there. The Y is nearly there, just need to mount the stepper which leads me to the frame. I have looked at many frame's and tried to come up with my own. There were three features I was looking for

i) I wanted the frame to be robust enough to support cutting aluminium
ii) I wanted to be extend the rails over one end for over sized jobs (thanks jazz)
iii) Thinking of the over size issue, I wanted the frame to be tall enough that I could mill out the lock on a door.

The machine will be inside so I'm looking for welded frame sides with bolted cross members. I also decided I didnt want the hassle of a moveable bed, frankly I want to get the thing built (this year), so left 110mm of Z travel from the tip of the spindle, I think thats enough for general use? I also decided at this stage to have two rails (in orange) welded to the sides as support for the drop-in welded bed frame (purple). With the exception of the top rails, everything else is 50x50x3. I havent costed it yet, will probabily have to revise on that basis alone but wondered if there was any feedback on the design so far. Thanks.

Hi Tony,

I am currently doing my first real build so take my word with a grain of salt but i spend a lot of time considering, redesigning, calculating and so on...

So looking at your idea i could not help but share my thoughts, even if they are quite influenced of my current design. I hope it helps though. Sorry, i dont mean to hijack your thread

What i don't like at your idea is that the diagonals actually don't reinforce the profile where the rails are.

I went on my design from 60x60x4 to 100x100x3 as i was faced by the same problem as you, great lengths and a lot of cutting and soldering.

So here i just twisted a bit my design to accommodate it to your measures and needs. Much less rails, much stronger, much simpler to execute and cheaper, as much less weight. I would like to hear what others say but i am quite sure is strong enough for routing aluminum, not scratching.

All in all there are 17.8 meters of 100x100x3 x 9kg per meter = 162 kg






My thoughts about bead and gantry:

I made my gantry design to be from 2 pieces of 100x100x3 soldered together, just to have in mind when considering the following.

For me to build a machine and later to upgrade it is not OK, i mean what you say for your Z depth. Please take a look below for my solution to this.
My Z plate is 500mm long. My useful Z travel is 200mm, but i will limit it to 180mm. However the idea is the bead to be deep but over it to have a cheap wooden structure 100mm high to serve as a removable table. So now the working area is raised and there the aluminum or normal jobs will be cut. The table can be made from a couple of MDF sheets glued together or whatever scrap. Even from ribbed inside wooden structure to weight less and easy removal.

So with everything soldered i would have quite versatile machine/ in fact its not for me the machine/ .


Of course you can add 2 x 1600mm rails and make the bed removable, but i don't see a reason for it as you can remove the wood bed instead and keep everything much stronger. I believe on my design there is no need to add anything or change anything, as even it looks simple is thought to withstand forces from all directions. The only thing that comes to my mind that can be bettered is to place everything at asymmetrical distances to avoid frame vibrations further



If you use Sketchup i will be happy to send you the file with the table i draw with your dimensions so you can play with it.

I hope that will give you some ideas .

PS. One key part of that design that i forgot to mention is that there are plates that fix the rails supporting beams. I will lasercut them, but they can easyly be fashioned from something else. They play the role of not permitting to the beams to vibrate left right, looked from front and also seal the profile end.

[TonyD]

Thanks Jonathan. I thought 260 was a lot as it was but happy to leave it there, if as I suspect this is the basic design I go for.

[Boyan Silyavski]

Just a note there about the Estop button: Buy a brand one. The cheap chinese ones have weak springs and stick sometimes right when you need it. I have el cheapo and it betrayed me a couple of times. For my new build i bought Japanese and the difference is huge. believe me, you will need an Estop button

[TonyD]

I spent some time today calculating the cost of the steel. Not sure its a useful metric (for discussion) but there are just over 30M in steel box in the design. I was quite dismayed to start checking on the web for pricing only to discover several sites quoting around £350, which was more than I had in mind. Then I came across a company called ISG Steel who routed my call to the nearest depot (I live in Berkshire). Thier quote on a like for like quantity of 50x50x3 steel box section was around half the websites I'd found up to that point, also they were friendly and when I mentioned I needed more than just the one length offered me a discount. From then on in I looked at how to cut the required lengths from 7.5M stock and came out at 4.2 lengths, which was dissapointing. I modified the design to use small 5cm lengths of steel to support the bed on each of the 5 side member points, instead of a continuous rail (Orange in the picture above) and that nicely got me to all the steel in 4x7.5M lengths. Once I asked for a quote including the top rail material of 90x50x3 the whole thing with shipping came to £220. It seems a fair price and much better than many of the websites I found.

[JAZZCNC]

Tony I pay around £26-30 depending on steel prices at that time per 7.5mtr of 50x50x3. This is from local steel supplier so I'd checkout any local steel stock holders because that 90x50x3 seems to be costing quite a bit. My local supplier delivers free because I'm just up road but he only charges £15 for 20mile radius and i'm sure other steel stockist's will be similar.!

[Skysurfer]

Tony, I'm heading into this size machine, any chance you could throw those sketches my way? I haven't even started, yet, so I'm trying to figure out what will suit me best (size wise). I have a load of steel in my shop at the mo, and I'm trying to use it all ('cos I'm tight;-)
Cheers,
Pete

[mekanik]

Skysurfer
Post 24 has the required info
Mike

[TonyD]

Skysurfer,If you cant find what you're looking for, let me know.
I have made progress last few months, I'll post some photos this weekend, maybe a video even. I'm close to turning on now. :)

[Skysurfer]

Cheers, Mike & TonyD, will take a look. I'm still playing with my Zen 7x7
Pete