Maximum X and Y Travel

[sagreen83]

So, as part of putting together my table, for my PRTAlpha 96 (48"x96") about a month ago, I centered the spoil / support board in the middle of the steel table. This is a big no-no with a single Z axis because the router (PC) is not centered in the middle of the Y axis. Doing this, I lost about 5 inches of my X travel.

So, I am going to have to re-build my spoil / support boards. I plan to offset 49"x97" MDF by about 2 1/2 to 3 inches to the X zero side of the table. This will give me about 2 1/2 inches before the stops on either end of the X axis. Does anyone else have a different recommendation on this?

Now... The Y axis is a completely different story. I have placed my prox sensors so that they are about 3/4" from my mechanical stops. This leaves me with about 49.3" of Y travel between the Y prox sensors. If I want my Y axis, using a 1/2" bit, to completely clear a 48" piece of material to be cut, it would seem to me like I dont have a lot of room to play here. So, a couple of questions...

1) How much travel (inches) is everybody seeing maximum in the Y axis?

2) How much room on the Y axis did you give between the prox sensors and the mechanical stops? I thought I read somewhere in the forum that you needed 3 inches to properly slow down the AlphaStep motors. No way this is going to happen because there just isnt enough room.

3) It appears that on the Y axis, you loose about 1" to either side due to the factory placement of the mechanical stops. It looks to me like the stops are hard set by the factory due to holes being drilled into the supports to hold the stop in place. Anyone tried to move these?

The bottom line is that I am trying to figure out where to initially place my support / spoil boards in the perimeter of the table. I had the table built to the specifications provided for the PRT steel table. Can somebody that has an Alpha 96 / porter cable tell me where they initially placed their support board to get optimal travel in the X and Y axis's

Thanx,
Scott...

[paco]

So, I am going to have to re-build my spoil support boards. I plan to offset 49"x97" MDF by about 2 1/2 to 3 inches to the X zero side of the table. This will give me about 2 1/2 inches before the stops on either end of the X axis. Does anyone else have a different recommendation on this?

I too, plan this...

Do you use prox. switches at EACH end of each axes? I plan to installed 2 prox. for zeroing and the rest would be limit switches... $$$$$

Are you now dreaming of 60-120 table Scott?!!

[fleinbach]

I to notice the off center condition of the spoil board but for me it's not much of a problem. I purchased the Prtalpha120 to have the extra capacity to cut larger sheets when necessary. 95% of the time I am cutting 49 X 97 sheets so having the 0,0 position 5" short of the maximum X travel range is not a problem. And actually I am able to reach 121 1/4 inches just enough to be able to get maximum use from 10' sheets using 1/4" bits. Actually I can get maximum use in the Y axis also with a 1/4" bit. On the X axis I have approximately 1" of travel past my Prox switches. On the Y it's only 1/2". Yes it's true at 30 in/sec you will over shot and ram the stops. But according to what I was told they have run the shopbot into the stops at 30 in/sec and the tool will survive. Not that this would be desirable.

As far as I am concerned the proximity switches primary propose for me is to zero the table quickly, easily and accurately. The function of stopping the tool at 30 in/sec is secondary. In my opinion the best protection from ramming into the table stops is built into the software. Table Limit Setting once set up will slow the tool down so it can't ram into the table perimeter. Though at this time it is not working properly but they are aware and working on a fix for it.

[richards]

I bought the alpha 120-60 machine because I needed the width for 60 x 60 inch baltic birch. When I first built the support board and spoil boards, I completely covered the table minus 1/2 inch on the sides for table cleaning - bad idea. Last weekend, I tore off the original support boards and spoil boards, placed a 48x96 support board and spoil board aligned so that I can place another 12x96 set of boards to get a 60x96 cutting surface. The support board and spoil board are offset to the right so that the new 0,0 position is about where the old 24,0 position was. The entire Y-carriage can be moved (-18,0) out of the way so that I have total access to the 96,60 table top.

My advice would be to buy a machine one size larger than the material that you're going to cut.

In my opinion, it would be better if the machines were built a few inches larger in both the X and Y directions to allow a little margin in placement of the router/spindle as well as allowing easier routing of the outside edge of full size material.

[fleinbach]

I forgot to mention. That 5" offset at the 0 end of the table is very conviniant for bit changes. I sit at that end of the table and when you run the tool to the X stop at -5" there is nothing under the spindle head making it very easy to change bits.

[sagreen83]

Paco,

Yes there are prox sensors for each end of both the X and Y axis. So theoretically you could use either end of the axis to position 0,0 whereever you want.

It would be nice to have a 60x120 table, but for the $$ I decided that I would not need it 99.9 % of the time. I think that I will probably move my prox sensors out to 1/2" from the stops on the Y axis and I should be fine if I position the support / spoilboard correctly.

Thanx,
Scott...