Well I must be mad
More to follow with pics
It's the PP that limits it as the DLL for the PP that can only run in 32 bit OS . That's why the switch to motion controllers USB or Ethernet has had to happen because the modern PP do not output 5vdc only 3.3vdc hence they do not have the power to drive the hardwareHi Stuart there are converters to handle handshaking.............http://www.epapersign.com/lpt2usb0/lpt2usb-features-and-functionality?gclid=CNLayMGdiccCFYI7aQodix8ChA
So my system is a core duo optiplex running W7 64 bit pro and it's fine no problems now I have the correct software , this needs to be the current ver in all cases else it will not run
Stuart
For touching off I use a 1" gauge block, and have never chipped a tool. I jog up until the block slides underneath, the down .01" and then up by .001".
I use air blast to clear chips. Tried coolant, and it was messy.
Hugh, the way I understand what you wrote is the tool is lowered until it touches, ( the way I do it). I understand the way KVOM does it, he raises the tool until it just touches. The difference is which way the backlash is taken up. On Most CNC systems this is not an issue, but I'm finding it is on mine.
maury
I have just had a first go with Fusion 360. Previously I have done 2D with Draftsight and CamBam so I was keen to see how Fusion worked for a sculpted part.
Here is my first part as a rendering and as a first cut. I found building the model quite easy (normal software caveats apply) and rendering is just icing on the cake. CAM for 3D I think I have more to learn but the software does what it says it will and no surprises.
You can clearly see the track of the 6mm ball ended cutter even after 3 operations. I think I either need a tighter finishing pass for the near horizontal surfaces or perhaps use a bull nose cutter rather than a ball, to leave small steps rather than grooves. Anyway a first step and one I am quite pleased with, the part is to be used in a dog guard in the car.
Mman
Hello Chuck
I like your 4th axis set-up. It has got me excited and thinking about making one for myself.
I see you are using a HUGE stepper motor and I can understand the need for plenty of torque; but you are driving the spindle through a comparatively small toothed belt. What about backlash in the belt drive and possible belt stretch ? Is this a real or imaginary problem ?
Regards
Mike
Stuart: If the learning curve goes over the vertical that's good, as you're then on the way back to horizontal! Despite a number of CAM/CNC issues with the parts shown, the majority of the time taken was in the actual design, not related to the machining at all. I'll be interested to see what you do regarding tooling plates. Early on I bought a large (20" x 14" x 1"), and expensive, piece of ground aluminium jig plate. I designed a tooling plate with lots of tapped holes, and reamed holes for dowel pins. So far I haven't got around to actually making it. For smallish parts I use a machine vice. A lot of parts rest direct on the machine table, and for those where I am profiling edges I use a sacrificial lump of ordinary aluminium plate.
Chuck: The helical gears look good. As a result of discussions on another forum I am looking at the mathematics of helical gears. I'd be interested in knowing a bit more about the setup used to machine them. Did you use an involute cutter, set over at the helix angle, similar to using a universal mill and dividing head, or a small slot drill making a series of passes for each tooth? If you used an involute cutter how did you calculate the equivalent number of teeth used to select the cutter? If you used a slot drill how did you model and/or calculate the tooth shape?
I'm a bit confused about the use of the 4th axis for thread milling. Some while ago I bought a couple of thread milling cutters from Maritool, but haven't had a chance to use them yet. However, I was under the impression that I could use the mill in 3-axis mode to generate the necessary helix for cutting both internal and external threads. Have I misunderstood?
Andrew
The calculations for ridge height versus stepover for a ball nose mill should be simple geometry, although it is built in to my CAM program so I have never actually sat down and done the maths.
Andrew
I have just had a first go with Fusion 360. Previously I have done 2D with Draftsight and CamBam so I was keen to see how Fusion worked for a sculpted part.
Here is my first part as a rendering and as a first cut. I found building the model quite easy (normal software caveats apply) and rendering is just icing on the cake. CAM for 3D I think I have more to learn but the software does what it says it will and no surprises.
You can clearly see the track of the 6mm ball ended cutter even after 3 operations. I think I either need a tighter finishing pass for the near horizontal surfaces or perhaps use a bull nose cutter rather than a ball, to leave small steps rather than grooves. Anyway a first step and one I am quite pleased with, the part is to be used in a dog guard in the car.
Mman
Chuck
Now you have me confused. You said in your reply 'the stepper motor isn't that big. It's a NEMA23, I think under 200 oz in' .
What stepper do you use for your helical gear work?
Cheers
Mike
Chuck: Thanks for the spreadsheet, it is pretty neat. I note that the spreadsheet uses the standard divide by cos of the helix angle cubed to get the equivalent number of teeth to select a cutter. It is fairly simple to derive the equation from first principles using the radius of curvature of an ellipse. However, what confuses me is that some sources, eg, Machinery's Handbook, give a revised formula with an additional term involving the cutter pitch diameter and normal DP. I'm not sure how this extra term arises. Apparently it is most useful for gears with high helix angles and low tooth count. That seems to apply to one of your helical gears, but presumably the gears meshed without any problems?
I have also seen another variation involving dividing the actual number of teeth by the square of the cosine of the helix angle and the sine of the helix angle. The example given was for 45° which of course works as sin(45) = cos(45). However, for zero helix angle, ie, a spur gear, the equation blows up as sin(0) = 0. There is also an equation involving the tangent of the helix angle and the helix angle itself, but I haven't had time to look into that yet.
Andrew
You have set my mind at ease, now I know you normally use the much smaller 200 oz/inch motor.
Mike
I still have that comfortable feeling knowing that Chuck's 4th axis unit works.
Mike
Thanks Mike,
It certainly shows me that Fusion 360 works and that I can start moving from 2D to 3D.
Mman.