straight lines being cut with a small bow.

[BigoleRob]

hey guys first time on here. im running (to the best of my knowledge) a PRT 120x60 brand new as of 5 months ago.

we have been making cabinetry for a hotel. and of course we found out alittle late that the machine has been cutting on a bow. over about six foot of "straight cut" you can measure somewhere near 1/32 of bow, in the same direction. so all x axis "straight lines" have this minute bow.

of course this 1/32 turns into 1/16 maybe bigger once lamination comes into play.

any advice or knowledge on this problem?

[Brady Watson]

First, make sure that the table is dead level. Then, park the gantry at one end & measure parallelism of the X rails, noting any deviation. Find the straightest rail and true the other one to match using your tape. Drop the motors from the rack and only using the gantry's weight, run the X car up & down the rails keeping your eye on each pair of v-rollers. Make sure they don't climb the rail or raise up as you are moving the gantry back & forth. If it does, adjust the bolts on the rails to the table to get it perfect. It could be that the gantry is climbing up the X rails in certain areas, also causing your Z issue. It takes time & patience to adjust the rails properly, but it will get that tool dialed in.

-B

[BigoleRob]

that also makes sense, someone has had there wheaties today. ill give it a look.

[bleeth]

They could also be dead level and parallel to each other but also bowed themselves. Get a good reliable straight edge and verify that as well. A wallpaper straight edge is a geat tool to have around for this. Otherwise, a good quality long level works also.

[BigoleRob]

SUCCESS.
I found my table not level and took care to level it between all 6 feet. a fun endeavor for sure. fixed that and moved to the second problem.

first I checked to se if my 0,0x0,120 rail was flush to the aluminum frame (it wasn't.) I then flushed that rail, starting on one end with the gantry opposite then moving it to my start end once I got to far to continue. after fluching my vrail as the manual showed

I used a piece of high quality pine as a spacer (sized to factory suggested span) and walked it down the length of the machine between the v-rails. sure enough I found my machine variably down the line somewhere near an 1/8 of an inch in or out. I then (using a partner) went down the line and loosened 3-4 allen bolts at a time and adjusted the rail to my opposite flushed rail.

my parts are now cutting really well, and have no issues with OA sizes or bowed edges.
thank for the info, sorry it took so long to post about this fix, day job doesn't slow down.