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May 24, 2018, 16:52:54 pm

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 on: Today at 15:23:05 
Started by Dougal - Last post by Bob La Londe
I used spiral milling to cut threads in the manner I described without damaging the threads before I used the thread milling plugin.

 on: Today at 15:04:52 
Started by fourchette - Last post by Bubba
Yes, Try Cut Width..

 on: Today at 13:55:49 
Started by fourchette - Last post by fourchette
ok. i feel a bit stupid...

with a combination of offsets, unions and layers, I managed to do it something similar.

however, for starters, it's a bit cumbersome and error prone.

But what i do not like is that when an isolation trajectory is completely inside a bigger one the following happens
1.  the smaller one should be given a negative offset (to isolate towards the inside instead of towards the outside)
2. the smaller disappears with the union operation (which kinda makes sense for a union but is not what i want)
therefore i have to manually do stuff.

Isn't there a simpler way ?

 on: Today at 13:29:06 
Started by fourchette - Last post by fourchette

I use cambam to mill my electronic boards (i use a V shape endmill for tracks and a straight line endmill for holes). It works great. below is one example.

However, I would like to better isolate the tracks but making several passes around tracks. Keep in mind that I do not want to make a big pocket that remove entirely all useless copper, but insead "turn around" tracks. I dont know the exact wording.

A friend of mine told me about that seem to do exactly this.

Isn't there some way i could do the same without much struggling with cambam ?

 on: Today at 10:43:20 
Started by Dougal - Last post by jk

If straight lead-ins (not arcs) are ok, see the attached file. The script of mine is used there.

Doubleclick ScriptEntity to see and change parameters.

 on: Today at 04:50:36 
Started by Dougal - Last post by Dougal
If you can stand a circular pass at the bottom you can start at the the top using a profile MOP and tangent lead out at the bottom. 

Spiral leadin.  Tangent leadout

That is how I do helical milling operations.  But I simply don't have those options for the canned thread milling cycle.  The major difference between the thread and milling being the milling operation doesn't matter if you lift or plunge the tool up through it.  Nor does it matter if you take another circle around.  But that can really make a mess of a thread.

I've been able to manually edit the .nc file to give the start and lead-in arcs I needed.  But it was slow and painful.  Involving spreadsheets and sketches to confirm the maths and offsets were correct.

It would be great if there was a more simple way.

 on: Today at 04:39:12 
Started by dave benson - Last post by dave benson
I could see now, that I need some force multiplication if I was going to use the 3kg solenoid.
On next attempt, I used a button Actuator which braked on the periphery of the rotor.
The picture shows the button “Centre Shaft” that the brake material would sit in.
To do this, I had to semi manual program an R70 radius in the ZX plane.
This went well. Pic 1

Next I made a capstan that fitted to the button housing and provided the necessary torque to activate the brake. Due to the space constraints I could only get 3 to 1 multiplication and I had to make quite a few of these to get it to operate smoothly (originally I  used a bush in the capstan but had to replace it with a roller bearing, which made all the difference).

This turned out to be a mini project all on it's own!

I then tested this out (ran it in one of the turrets) but  disappointingly it didn't have enough braking capacity, which meant that I'd have to install a heavier spring in the button but I wasn't sure how much extra torque there was left to do this.

So I conducted a little experiment and took the brake out and sat it on the bench, then placed a small plastic jug graduated in ml and filled it with water until the  spring popped. I did this a few times to get an average.

It turned out the force was 25 newton, the same as the solenoid and so with capstan multiplying the force 3 to 1,  I really could increase the spring pressure but  for various reasons I didn't like the idea.

So  I set that button aside (I'd made a couple) and ordered a 5kg solenoid  for it.

Over the next week or so I read some engineering and Mechanisms books and haunted the web to see what other people had done with braking mechanisms.

Then it dawned on me that a braking mechanism requires a fairly high force to operate that's the nature of the device, I now realised that I needed a Indexing Mechanism instead as they don't require anywhere near the same force as a brake to operate.
So was there another way to achieve what I wanted with the components I had already made.

It turned out there was, I modified the Disk Rotor by cutting 120 (3mm scallops) out of the   periphery.

I then installed some drill rod in the shaft of the button (this engages with the scallops) so I didn't have to make any new components only modify the ones I already had.

This finally did the trick I could now use the 3 kg solenoid  and a comparatively small spring to get the job done. Pic 2


 on: Today at 04:32:20 
Started by dave benson - Last post by dave benson
Another Update on the progress so far.

Well, I machined up the first set of  Calliper bodies using the slope property in the profile mop. (17.32 deg)  with  a 3 mm cutter and  0.1 mm steps.
I also left a 0.25 mm clearance on each end of the pocket so that the pad would float freely.
(this would come back to bite me later)

I then cut out the Brake pads, which I found very fiddly and hard to set up in my present vice,
and  I new I had to order a  5 in machinist’s vice to get any form of repeatability in my work.

I then assembled the calliper and tested it in the bench vice with a dummy rotor.
With bright led torch and a magnifying glass I actuated the mechanism with a pair of pliers.
And everything looked good, the pads opened and closed, but worryingly needed more force than I expected to operate.

The second problem arose when I rotated the rotor, there seemed to be a bit of backlash, and on investigation found that the pads were firmly attached to the rotor but moving in the pockets (with that extra clearance I gave them).

To address the first problem I machined up a new set with the minimum wedge angle the geometry would allow (to get the most mechanical advantage) and also took the clearance in the pockets down to 0.1 mm).

Ultimately this was a fail, cleaning up the pockets did reduce the lash to a very small level, but the force required to operate it 6 kilogram region and as  I'm committed to using as lest power as possible so I had to come up with another solution that only required a 3 kg force solenoid.

See next post

 on: Today at 02:02:39 
Started by Dougal - Last post by Bob La Londe
If you can stand a circular pass at the bottom you can start at the the top using a profile MOP and tangent lead out at the bottom. 

Spiral leadin.  Tangent leadout

 on: Today at 00:59:40 
Started by jim1108 - Last post by jim1108
This happens in version 1.0 and .98 as I recall.

When copying a MOP to use as a "free pass" and changing only the spindle speed and tag(comment) I would think it would reflect that in the copied MOP, but does not. The free pass MOP is right after the original so a tool change is not necessary. Sometimes a free pass is needed, but I like to change the spindle speed and have the tag(comment) in there as well. If the feed rate is changed, it updates correctly. No big deal, just thought I would throw it out there.

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