[nquantum]

I will design CNC for wood/acrylic/aluminium and working area is 60cmx90cmx15cm. I plan to use T-slot for table top. I thinking about MDF, Plywood and T-slot. Then decision for T-slot due to it convenience for mount objects. If I use MDF or Plywood then soon I will go T-slot anyway later. So why not now, and I can also mount MDF, Plywood to T-slot too if I have to.

Question:

1. Type of T-slot table top suitable to choose? Is there standard/size to choose like aluminium extrusion? It made from aluminium right? or metal?
This one I can find in local shop is here is good enough? It made from aluminium 17mm thick/12cm wide. Pic1

2. I see one cnc from youtube change T-slot aluminium tabletop to sheet of metal. Due to it flex unlike metal, here is link.
https://www.youtube.com/watch?v=zdllMYgsAkg&t=6s

So it will be problem for T-slot?
If I have aluminium extrusion bar in the middle under T-slot just like this machine Pic2 will solve problem? Since those 2 aluminium extrusion in middle will support T-slot tabletop I guess.

3. T-slot wide is 12cm normally can I cut shorter? Should I? Example is 10cm. It will effect it strenght/stiffness? Cause it will effect the length of x-axis. That it must be step of 12cm like 60cm , 72cm , 84cm for example for that T-slot will fit without cut.

[wizard]

I will design CNC for wood/acrylic/aluminium and working area is 60cmx90cmx15cm. I plan to use T-slot for table top.

The term T-Slot covers a wide array of materials and quality. It is probably a good idea to be specific.

I thinking about MDF, Plywood and T-slot. Then decision for T-slot due to it convenience for mount objects. If I use MDF or Plywood then soon I will go T-slot anyway later. So why not now, and I can also mount MDF, Plywood to T-slot too if I have to.

T-Slot isn’t always the most economical way to a table solution. This especially if you are going to mount a spoil boards.

Question:

1. Type of T-slot table top suitable to choose? Is there standard/size to choose like aluminium extrusion?

There are many options here! There are purpose made extrusions, you can gang up common T-Slot framing members, or go the machined plate route. You can also build up T-slot solutions from dimensional materials.

It made from aluminium right? or metal?

Aluminum is a metal. That being said you can buy machine tool tables sub plates and fixture plates in aluminum, steel and cast iron If you have the money you can get just about anything material wise.

This one I can find in local shop is here is good enough? It made from aluminium 17mm thick/12cm wide. Pic1

Did the pic come through?

2. I see one cnc from youtube change T-slot aluminium tabletop to sheet of metal. Due to it flex unlike metal, here is link.

everything flexes to some extent or another. From a machine implementation standpoint you have two choices. One is to do the engineering calculations to determine what meets your needs. The second is to take a wild ass guess.

The approach taken in that video is a bit strange and the mechanical arrangement of that entire machine leaves a bit to be desired. The plate probably helps just by adding mass.

So it will be problem for T-slot?

What will be?

If I have aluminium extrusion bar in the middle under T-slot just like this machine Pic2 will solve problem? Since those 2 aluminium extrusion in middle will support T-slot tabletop I guess.

Support always help but the bigger question I have right now is this : is your machine already built? If not consider a robust design for your machine.

3. T-slot wide is 12cm normally can I cut shorter? Should I? Example is 10cm. It will effect it strenght/stiffness? Cause it will effect the length of x-axis. That it must be step of 12cm like 60cm , 72cm , 84cm for example for that T-slot will fit without cut.

I’m not sure what your issue here is. You either design your machine for the hardware you can get or modify what you can get.

[nquantum]

The term T-Slot covers a wide array of materials and quality. It is probably a good idea to be specific.

T-Slot isn’t always the most economical way to a table solution. This especially if you are going to mount a spoil boards.

I'd like to be more specific about T-Slot material and quality you say. But that reason why I post here to ask. Coz I don't know. I plan to work with aluminium/wood/acrylic. So spoil board is may not ideal. It will wet from coolant when work with aluminium isn't it?

There are many options here! There are purpose made extrusions, you can gang up common T-Slot framing members, or go the machined plate route. You can also build up T-slot solutions from dimensional materials.

Many I see OK! I know some yes. 20x20 30x30 20x40 aluminium extrusion etc. for CNC frame. I even see some machine use 20x20mm aluminium extrusion for tabletop. But I hope you can narrow down here. The one that normally DIY CNC that use for small project like this. It may not perfect is okay.

Aluminum is a metal. That being said you can buy machine tool tables sub plates and fixture plates in aluminum, steel and cast iron If you have the money you can get just about anything material wise.

Did the pic come through?

I mean I've see some tabletop made from steel T-slot like some with aluminium. That why I mention. I ask the reasonable material to go for. This will be personal use not company not corporate. Also I'm not that rich to just buy anything. Save money is always good.
You should see picture the first left one is from CNC local store near my location. Any comment?

everything flexes to some extent or another. From a machine implementation standpoint you have two choices. One is to do the engineering calculations to determine what meets your needs. The second is to take a wild ass guess.

The approach taken in that video is a bit strange and the mechanical arrangement of that entire machine leaves a bit to be desired. The plate probably helps just by adding mass.

What will be?

Support always help but the bigger question I have right now is this : is your machine already built? If not consider a robust design for your machine.

I've design already.. but not build yet. Still minor adjust here and there. Something still be question. So I keep search and post some. And sorry for I can not that specific it all.
Now that I ask about choose tabletop so I know how thick it is then how add to tall gantry/distance to spindle.

[wizard]

If the intention is to do a lot of Aluminum machining you will want an all metal solution. Like you mentioned coolant becomes a problem around wood products.

As for which avenue is best for you I can’t say mainly because everybody has different approaches to these issues. More so what can be found locally has a huge impact on ones build, especially if cost is an issue. I’d certainly consider anything that comes up locally as used tool table / frames. Score the right stuff used and you will likely redesign around that used stuff.

For example about a year ago a guy scored a bunch of large aluminum extrusions, used ones, for a song. In that case it makes perfect sense that design around the materials at hand. For most of us the goal is to get a suitable machine for an extremely low cost. If you are forced to buy materials at retail prices then you need to work out which is the most cost effective solution with what is available locally.

I often advocate steel. The reason being steel is often cheap compared to other materials. At least it was, the going rate for scrap was often 10 cents or less a pound. Steel often has assembly disadvantageous but there are a lot of hidden costs with T-slots. For smaller machines a combination of materials might be a good idea.

For example Blanchard ground steel plate is fairly easy to buy and more or less cheap. You simply build upon the top of that plate. That is mount the rails directly upon the plate. Along with the drive hardware which can implement a moving table or moving gantry solution. The problem here is that suitable plate steel is pretty heavy. But heavy isn’t bad when it comes to machine tool performance, especially in a base. Again it comes down to what you can handle locally.

Beyond all of that are T-Slots the best solution? An array of holes can do wonders. Imagine a plate with 12M holes on 30mm centers for example. Some people seemed to be obsessed with T-Slots but if 80% of your work is off a spoil board it might be a waste. Also the T-Slots in a lot of the aluminum extrusions out there are not all that robust.

In a nut shell I can’t say which approach is best for you.