I think most of the high-volume lumber processing operations over here use vision to size the lumber before cutting. For your more limited application of simply trimming the edges of boards, something like you suggest could work.
I would suggest that your lever have the encoder at the pivot, with a spring to keep it pulled against the board. Just use the encoder value to calculate board width, then drive the moving motor into position with a lead screw or timing belt axis. Use some hal logic to indicate whether a board is present or not, so your motor can move at a reasonable rate back to its inboard position. How fast are these boards moving? -- Ralph ________________________________________ From: Viesturs Lācis [[email protected]] Sent: Tuesday, May 13, 2014 5:55 AM To: Enhanced Machine Controller (EMC) Subject: [Emc-users] OT: need some advice Hello! I would like to ask for some advice, hints or ideas for a pretty simple machine. The task is to build a machine which would process side edges of wood boards. The thing is that board width varies in range of 80 to 300 mm in a random, unpredictable order. There are 2 motors - one for each side. What I have in mind - boards are based along a fixed slide, so one motor is firmly mounted, the other motor is supposed to be repositioned for the width of particular board by stepper motor. The problem is how to measure the width of board in most simple way. I was thinking about some ingenious way of using quadrature encoder - pulse counted by some Arduino, which would be programmed to issue step/dir for repositioning stepper in some electronic gearing ratio (and home it to a switch when dedicated button is pressed). I created a small sketch of my current idea: http://picpaste.com/scheme-pemLgnsD.PNG Basically it is a lever, fixed at one end and the other end attached to timing belt or whatever, that turns an encoder. Initial gap is smaller than minimum board width. There would be some small error as the attachment point of timing belt on the lever end would not move exclusively perpendicularly to board movement direction, but that might be acceptable. The problem with this is that once the board passes through, the spring will return that lever to starting position very quickly and the motor might not manage to follow, so I cannot think of a nice way to adjust, how fast it returns back. I will appreciate any feedback! Viesturs ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
