pBot newbie needs advice....

[JimmyD]

I am about to purchase a new PRSalpha and need some input/advice. I am not new to CNC, I have a plasma cutting system that I built myself so I understand most of the issues. (I can't type complete words as evidenced by the title of this post....:) ).

I want to get the 96x48 but the room that I want to put the Bot in is not the ideal size. My questions are 1) how much actual clearance do you really need around the system for human access? How many of you purchased the 48x48 and later wished, for good reasons, that you had purchased the 96x48? Conversely, how many purchased the 96x48 but never really used its size capabilities?

Thanks for any inputs.

[scottp55]

Might help.
http://www.talkshopbot.com/forum/showthread.php?t=18600

[khaos]

I have about 30" on the sides and maybe 30" at the top. But about 20' at the bottom. Sheet goods are not loaded over the rail on mine.

[khaos]

You can see pics of my setup here (http://www.talkshopbot.com/forum/showthread.php?t=507&highlight=crispy).

[scottp55]

Jim, If you click Joes link, don't miss clicking on the link in #13!:):( :eek:

[steve_g]

Jim...
Due to cramped quarters, I bought the 48 X 48. I don’t build cabinets and so don’t often need a full size machine. I have, however, gotten quite good at tiling. My garage is set up so that when the door is open I can hang half a sheet outside... What I really wish I had was a 5’ X 5’ for Baltic Birch sheets..
SG

[Brian Harnett]

My first shop I had the bot in a 12x16 room with doors I could open to feed in sheets It was a working size. the actual footprint of the machine is 5'x10'

[myxpykalix]

My machine is a 5'x10' machine and I stuffed it inside a 16x24 shop and found myself sucking in my gut to get around it because of other tools. I think you need, at minimum 24" to 36" on all sides for clearance to be able to walk around it.
When i decided to go to a cnc i bought the largest model available at the time and incorporated a indexer into the table. So i can put a full sheet of plywood on the table and also run my indexer without having to move any tools.

Now having said that, i can tell you that probably 75% of the things i've cut could have been done on 25% of the table. So in my case i opted to "go big" and there is not any job i have to turn away because of size.
Regarding size...i'd rather have it and not use it then to not have it and need it.:eek:
I would buy the largest table your wallet (or wife) allows you to buy:rolleyes:

[gundog]

Because of the design it is better to have room on the ends than the sides. If you use vacuum hold down access to the sides is not that important but if you plan to screw or clamp things down you need to access the whole table and will need room to move around it.
Mike

[gerryv]

Assuming you have vac. hold down, you could get away with pretty much zero clearance along the back as long as you're capable of clambering up on that part of the table over the side occasionally to do things like mounting spoil boards. Enough space to comfortably squeeze in would be better though, say 14-18". Problem is, you might also want to get in there a lot depending on your hold down choice is vac. or not so zero clearance is a no-no if that's the case.

You can also have a quite narrow aisle up your "wall" side. There is a very good reason for not having it as a tight squeeze space though. The stepper motors stick out several inches and if you happen to be in there when the table is moving (bad idea) they are at a height that makes most men of average height... well, you get it. Best to call tech support and ask if the stated footprint includes the steppers or not.

You'll also want at the very least the length of your longest anticipated pieces plus your body size room plus some wiggle/elbow room on the front if at all possible but if not then along the open side in which case you also have to allow perhaps another foot back to front for the area the gantry blocks. Side loading is a pain but doable IF you have a good back. Even if you do side load, you'll still be at the front of the machine a lot if you have a typical setup for your home position.

Steve makes a very good point about the 5'x5' option so that you can use that size of Baltic ply. It's used for a lot more than just cabinets because of it's superior quality. Also, with the availability and good precision of track saws today, knocking down full sized sheet goods for use on a smaller cnc is usually pretty fast and painless.

That's just this guy's thoughts though, not advise. You might decide you need a bigger table and or shop after the first month.:eek:

[coryatjohn]

I have a 60x96 and it resides comfortably in a 12x22 room. The top of the machine (or back) has only about 12" of space, just enough for me to squeeze through when the gantry isn't in the way. I rarely have to visit that side of the table so it is fine to have it tight on the back side. The ends need the most space and one end should have at least 9' free so a full sheet can be maneuvered into position.

You can setup the machine in several ways so if you have more room on the ends, you can place your computer and vac controls there. I had more room on the front so I have the controls there.

[JimmyD]

Thanks to all of you for the excellent input. I have decided to go with a 60 x 60 and not have vacuum after reading about crispy bots.

[gundog]

Depending on what you plan to cut I would not let the crispy bot story stop you from using vacuum many of us use vacuum with no issue. I would never think of going back to clamping or screwing parts down. I have been using vacuum for 4-5 years with no issues. With that said having access to clamp or screw things is sometimes handy when parts can't be held by vacuum.

My next table will be 5'x10' and have a 54"x96" vacuum zone the rest of the table will have an aluminum extrusion for clamping fixtures.

Mike

[scottp55]

Yes Jim, Didn't mean to spook you about vacuum ,just to make you aware. Even on the Desktop plans are underway for vacuum Jigs on certain items, as it vastly increases speed,reduces waste,and let's us use entire work area easily.

[coryatjohn]

Depending on what you plan to cut I would not let the crispy bot story stop you from using vacuum many of us use vacuum with no issue. I would never think of going back to clamping or screwing parts down. I have been using vacuum for 4-5 years with no issues. With that said having access to clamp or screw things is sometimes handy when parts can't be held by vacuum.

My next table will be 5'x10' and have a 54"x96" vacuum zone the rest of the table will have an aluminum extrusion for clamping fixtures.

Mike

I've done this with my 60x96. 48x96 is vacuum, the rest is clamp area. The vacuum is really a great addition. I use it whenever sheet goods are involved. Trying to cut a 1/4" sheet of plywood that's not perfectly flat is a problem unless you're using a vacuum hold down on the sheet. It's nearly impossible to secure such goods otherwise.