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]

Silyavaski. Thanks for taking the time to modify your model with the dimensions I am looking for. I have to say your frame design does look so much more solid than the one I designed. The one one constraint I have is that I need to move the machine in the house so I cant have it all welded. I can see though that if I made the cross members you have proposed as bolted rather than welded, this might work. I'll have another look at the Z height and see what that means for the rail height. Thanks again. Tony.

[CraftyGeek]

Tony - it may be worth seeing if you have another local steel yard near you. My local supplier charge £4.1 +VAT per meter for 50x50x3 (£147.60 for 30m) as a base price & charge less than that if you order a reasonable quantity. I also get them to cut some of it to size for me - depending on quantities, they charge 50p per cut or less...this means I can fit it in my car & pick it up myself removing the delivery charge as well as saving me time cutting stock to size.

[Boyan Silyavski]

You guys are lucky to live in UK. Here in Spain i think in kg. Roughly any profile costs 1kg=1euro at the big warehouses. Unfortunately no near where i live and they don't cut to size. As i don't have a band saw i have to order from the local metal shop. If you befriend them they cut to size and sell it for 1.50 the kg with the work. if you don't know them they sell it for 2euro per kg and you pay the cut extra and that if you are lucky that they pay you any attention...

Hence my designs are influenced by the KG and by the 6 meters length. Guess who i will be bringing some beer tomorrow

[TonyD]

I've been caught by the CNC bug again :)
Silyavski emailed me a model in Sketchup to play with which convinced me to ditch Visio for my drawing and start again in Sketchup. As I tried to explain to my wife "the guys on the forum made it stronger, cheaper and lighter", which is I guess the power of good design. Trying to manage the constraints of cost and size I ended up going for 80x80x3 due to an inherent constraint with my Y Axis (which is built), which then left me trying to get the frame out of only two lengths of 7.5M stock, which led me in the end to cut the legs down to 350MM from 500MM. I phoned around today and a local Steel supplier quoted me £50 ex Vat per 7.5M length of stock. Now that its down to just £138 with VAT and delivery I'm happy. Bonus is the machine can be carried through a doorway so no bolting. So thats my current plan. Thanks for all the input, any other comments welcome.

[Boyan Silyavski]

Hi Tony,
i forgot to tell you but you went to exactly the same conclusion like me. The 80x80x3 is the size of profile that is at the golden middle point for weight and strength and value, also permitting this type of design. Great that you figured it on your own.

Today i went after work to the lazy guys at the metal shop and urged them for my profile. After helping them to cut i figured one point more. Its not a real necessity though. As i have ordered 1x 6m new profile and used some scrap they had, there was i piece of 100x100x4. So i figured at the last moment that the 80mm pieces could be even stronger if made from that. Ask them if they have by chance some scrap 80x80x4 just for the 80mm pieces. It will not raise the price. Just give it a try.

Hey, now i want small legs for the machine i am building

[JAZZCNC]

Tony The design would benefit from one more support for bed has the centre distance is on the wide side and could cause bed flex.
It also definitely needs some triangle braces in the corners to help hold frame square.

[Stupoty]

Tony - it may be worth seeing if you have another local steel yard near you. My local supplier charge £4.1 +VAT per meter for 50x50x3 (£147.60 for 30m) as a base price & charge less than that if you order a reasonable quantity. I also get them to cut some of it to size for me - depending on quantities, they charge 50p per cut or less...this means I can fit it in my car & pick it up myself removing the delivery charge as well as saving me time cutting stock to size.

Do you have the name of the stockist, thats a fairly good price :)

i always check metals4u.co.uk for steel and their about £60 + vat for 6m

stuart