We are using a new Rover 23 to drill and size melamine panels for kitchen cabinet boxes. When we run the panels we size them using the router and then drill for dowel holes. The hole pattern seems to run out when going back so the floors seem to run out on the gables, being flush on the front and ending up projecting on the back. We have noticed a small amount of warpage on the panels, but this problem seems to be greater than that. Has anyone else seen this kind of problem?
Are you using single or multiple spindles for either of your drilling operations? Do you know which holes are off, vertical or horizontal? Do you have your vaccum pods DIRECTLY under where you are doing your horizontal boring? Does the floor protrude below the end or vice versa?
Brian Personett, forum technical advisor
A second message was posted by the author of the original post:
I am finding the horizontal holes to be the biggest problem. I drill these with one drill as it is the only way to parametrically run the floors. The problem is the worst on small upper floors which will only fit on one pad. Yes, they protrude below the end gable at the back and are mostly flush at the front. There is no exact symptom, panel to panel--only general patterns which typically have the floor flush at the front and running down by about 1mm at the back.
First, identify what specifically is wrong with the boring (which holes are out, which way, and how much). Inserting steel pins in the dowel holes gives you a better reference than trying to measure to the edge of the hole. From this you can come up with a list of likely suspects.
For example, if you find that the horizontally drilled holes are out in the Z direction, it would probably be good to start by checking if your horizontally bored panels are pulling down flat. I'm not sure how your Rover operates, but you need to pull a panel down and then run around the top surface of the panel with a dial indicator mounted to the boring head. If you don't change the Z position, but your indicator reading changes significantly, you have discovered a fixturing error. This may be corrected by machining pods or rails, buying flatter panels, or just being more careful positioning your pods.
It's going to be a detective thing. You may even find more than one cause for your problem.
1) The bits are wandering. A bad grind job and bits that are longer than necessary make this situation worse. Also, the smaller diameters tend to wander more.
2) Some pods are pulling down sometimes and not pulling down other times. Check out pod levels, gasketing, and plumbing.
3) There is a mechanical problem in the machine. Use a dial indicator to check Z axis backlash and tool carrier tracking. Also use the dial indicator and strike off of the bottom of the horizontal drill while leaving the drives on. Lift, pull, and twist on the tool carrier to see if there is slop in the mechanism. Also jiggle the horizontal drill unit itself to see if it is loose.
It could certainly turn out to be none of the above, but this is a start.
Verify the level of the machine. A twisted frame can cause this. Slow down your horizontal drilling and see if things improve. If they do improve, the part may be moving some, or the drill is drifting on the banding before penetrating the panel edge.