I’d love to hear from other Foreman owners. Mine drops the Z axis and crashes the bit into the spoil board about 30% of the time or more, when I activate the Emergency stop.
Of course, the E-stop has to be checked every time you power up the machine, so I’m concerned that I will have bit damage due to this. I asked support, and their response is: It’s going to be possible since you have the weight of a 2.2 spindle.
To be fair, I have the exact same spindle on my 2 year old Journeyman and it doesn’t crash if I use the E stop on it. Can any of you reflect some light ? I’m really disappointed overall, and I can’t believe the new Elite series has this issue.
Anyway, if you own a new Foreman, could you let me know if yours does this?
I’ve had this from time to time when I had my 2.2kw water cooled spindle on it. Seems like it’s not a big issue in the hobby cnc space and the Onefinity isn’t the only CNC brand this happens to (I read this here: VFD Spindle dropping down when turned off - Carbide 3D Community Site). Those with Makita routers will most likely never see this happen.
it has to do with the pitch of the ball screw on the new z20 (steeper, so it moves faster) and the weight of the spindle. you can avoid this by adding a break to the z slider motor, but that adds a bunch of cost for something that isn’t common.
I’ve tightened the grub screw on the z slider white wiper down in the ball nut a bit and it’s holding tighter. If you over tighten, your z slider wont move, if you under tighten, your z slider wiper will come out along with all the balls. When I say tighten, I mean like a 1/8 turn at a time. Very, very little. That will most likely get it fixed up.
I do not have the Elite, but do have a Woodworker with a pre-release BZ assembly. My heavy ATC spindle was doing the same, and I ended up purchasing a stepper motor with a break (Note: I built my set up myself, and replaced the stock steppers right away with higher torque motors from the start). It also didn’t happen all the time, and it typically was a slow downward movement, but I too did not want to risk breaking expensive end mills.
I believe the new Z assembly has a much higher pitch ball screw (compared to the original), which adds to this (particular) problem.
They do sell add on electric brakes, but they are rather expensive. If you go that route the brake can be wired to Masso in a variety of ways - I added mine to my overall E Stop safety circuit.
Sorry @MyersWoodshop, just saw your reply after I hit send
I have the Elite Woodworker with a 2.2 spindle and it is difficult to move the spindle up or down by hand with the machine powered down, go figure.
Cursory search comes up with a lot of parts under $50, which seems like a pretty cheap fix, even after adding some other parts like a solenoid and additional wire.
If you can provide any tips on integrating the brake with Masso that would be really useful. Otherwise tightening a plastic wiper to add resistance doesn’t seem like an optimal solution to address this design issue.
I think with the encoder on the end of the stepper motor it would be difficult to add a brake to the existing motor
the alternative to an electromagnetic brake could be a constant force spring or a positioner/retractor/balancer.
This is the option I looked at before deciding to purchase an all in one solution of a new motor with brake - Spring Applied Power-Off Brakes | Teknic, Inc.
It took me a while but I found a supplier of a high torque Nema 23 - most were Nema 24 and I wanted a direct drop in solution.
As for the Masso wiring, I have one relay module dedicated to my safety circuit, similar in concept to the following:
I have the relays controlled by my E stop circuit (ES output) from Masso, and the brake 24VDC+ wired NC. When the E stop is activated, or the power to my system is off, the brake engages.
So, I understand what has been said in response, but… many of you, I think, are of the opinion that power is being removed from the system, and that simply is not the case with the Masso controller and it’s motors.
When I press the E stop on the Masso, the green lights that indicate power at the motor are still illuminated, which indicates 36 volts are still sent to the motors even though the E stop is engaged. The red status lights come on indicating an alarm condition, which halts that axis (all 4 turn red, BTW).
So, I guess that I can’t understand why, since it has power, doesn’t it “lock” the motor just as it does when sitting around with just the green lights on, you can’t move it by hand and it certainly doesn’t just fall while it’s sitting there.
I do not have the Masso closed loop stepper motors, so have no way of testing them, however my understanding is that the driver enable circuit will cut the coil current to the motors - at least that is what my drivers do. The green light may just indicate there is power to your driver.
It does appear it’s cheaper to buy a NEMA 23 stepper with integrated brake than purchasing a bolt-on front-mounted spring-actuated brake ($195 plus shipping in 8mm shaft size)
Rear-mounted brakes are cheap, but I haven’t found any discussion about retrofitting one to any of Masso’s closed-loop-equipped motors.
I have the Journeyman Elite with an 80mm spindle. Same thing happened to me. The bit went straight through the piece and spoil board. It stopped when the chuck rested on the piece i was working on. I did not expect that when I het the e-stop.
are you saying the spindle is still running (powered) after you hit e-stop?
The other cost would be a driver for the new motor. Stepperonline sells Nema 23 closed loop steppers with electric brakes - most Nema 23 are fairly low torque. They also sell the closed loop driver and cables as well.
I personally did not like adding a new hardware component between the motor shaft and coupler/ball screw, and liked the simplicity of the all in one motor, but I also am using my own installed motors and drivers in my own enclosure so I may have a bit more flexibility with respect to options.
I think he is referring to the functioning of the stepper motors.
The ones on the Elite are only 1.2nm themselves.
I honestly can’t say. I was banging on the spindle stop button when it happened. All I can tell you for sure is that the spindle was able to cut through 1.5" of particle board and give me a nice smoke show as well after hitting the e-stop.
Hey Tom, hey Jim, hey George, hey all,
Jim @Pleased2fly, since I don’t know your Masso-to-VFD circuit, does hitting the emergency stop button make the spindle halt?
I don’t know, would the bit go through the workpiece AND the spoilboard when the spindle was unpowered (a safe stop mode on VFD should be the case on pressing emergency stop if the entire system complies to IEC 60204-1)?
I will retest soon. Seems like a lot of energy would be required for that much damage, but the bit was spinning at 18k and it was directly on the piece when I hit the e-stop. Also, it was a tapered bit, so maybe the right combination of things allowed it to coast through like a hot knife through butter?