Tom Gardner (in ) said:
[ Paragraphs reordered ]
| My production requirements are only 800 per day but I can only
| dedicate so many man-hours so I need 300 per hour. Cycle time has
| to include material handling and pee breaks.
Ok - this essential info was missing - and is necessary to have a
starting point.
| I do it now with a 3 hp router swinging a 1.5" bit. The block fits
| in a sliding jig on linear bearings. The operator slides the jig
| across the bit and the block drops in a barrel. It takes about 4-5
| seconds. Not too bad, but I'm worried about repetitive motion
| injuries and the routers only last 4 months.
I suggest hitting E-Bay until you find a good price on a 5-10 hp
industrial spindle and a VFD. If the spindle hasn't been abused, it
should last a very long time. I use a 5 hp Colombo spindle and Delta
(not the tool co) VFD for CNC routing and expect that they'll outlast
me.
It would not be difficult to move your sliding jig with one or a pair
of micro-steppers and set up the jig to clamp while in motion and
release at extremes of movement. That would allow the operator to
drop the block into the jig and press a pair of buttons (one for each
hand), then reach for the next block while the cut is being made. You
should be able to feed the block past the cutter at 3-4 in/sec
(180-240 ft/min). Once the cut block has been dropped, the jig can be
retrieved at a still higher speed. You'd need a PC (an old, recycled
386 would probably do) and a stepper controller to drive the motors.
Using steppers makes it easy to control feed speed and
acceleration/deceleration of the fixture.
If you follow the link below, you can see what the controller would
look like. Your machine, of course, would only be a single-axis
machine and only 1/3 as complex as the JBot shown on the web page.
| My biggest concern is the possibility of repetitive motion injury
| so, I'd rather spend the money to automate rather than taking the
| chance of somebody getting hurt.
Well, the operator will need to move - and the movements will be
repetitive... unless you set up a system to pick blocks off a pallet
or out of a box. :-)
Actually, I think it'd be fun to build something like this! E-mail me
if you'd like help.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto