Here we go again . . . MK4

[Nr1madman]

It's mechanical porno!! ;)

[routercnc]

Cheers guys. It's very satisfying when it all works so glad you are enjoying it too.
For anyone thinking about jumping to F360 then I'd say don't hesitate. Its a powerful bit of software and is daunting at first but start simple and go from there.

[routercnc]

I managed to finish all 16 inserts, so another job done:


All the Y and Z axis material has arrived from aluminium warehouse. All fine except they sent me 5" round instead of 5" square. This is to make the block which holds the spindle. Quick phone call and they sent me the 5" square for free and told me to keep the round:


So onto the Y axis sides. Here is the CAM:


Laying out the blank:


Holes:


Profiled:


Holes tapped:


Then the corners had to be filed square to take the stepper bracket:


Edge holes drilled and tapped:


The second one was made the same way but snapped a cutter with the adaptive being effectively too aggressive. Actually it was my fault as I did not align the blank quite right and so the cut was too wide as the stock was not where the software thought it was. Anyway, we got there.

Couldn't resist a dry assembly to check it all fits:



There will be a piece of bent sheet over the front and rear, so checking this will fit flush to the stepper bracket:


Then onto the Z axis. Here are the raw stock parts:


Top plate being set up:



All for now.

[Nickhofen]

Wow nice work so far!!!

[routercnc]

Thanks for all the kind comments.

Onto the top part of the Z axis. Main holes roughed out.


You will notice that it is all offset to the right and the front. I made an error setting up the job and started to worry there would not be enough stock. In Vectric Cut2D the job always starts at 0,0. So you need to find the stock edge, go in say 5mm, and then zero out there. Then run the part which will give you a margin around the edge. In F360 I defined the stock in the software (which was 5mm larger than the part) and should have zeroed out on the edge of the stock. But instead I used my old method (by habit) and moved in 5mm then reset. The net effect was that the part was 10mm over to the right, and 10mm forward. Would it fit on?

This hole was supposed to be 5.5mm from the edge - looks like I might be lucky!


Counterbores done and used to hold the part:


Profile cut - ooh, just fits!


Then I walked in the 2 holes for the linear bearings. This is in case I ever make the power draw bar spindle and holds the chrome rails which the PDB mechanism floats up and down on.


When I was machining these holes I was removing 0.02 mm at a time (from the diameter). I noticed it was consistently taking away material from the half of the hole nearest me, and nothing off the other side. Now these are small distances, and within the 0.05 mm ballnut backlash so could be that, but I did lots of passes and spring passes one after the other and it always cut on the side nearest to me, as if it was progressing / loosing steps in Y- direction.

Here is the part trial fitted (on top of the sides which are still raw stock):


You can see that this also has stripes where the roughing stepped down on each pass, even though I did a full depth finishing pass. I checked for play in the Y ballnut and ballscrew mounting bearing and all was well. I pushed and pulled the spindle and all seem OK (well, as stiff as it always was anyway). I'll keep an eye on it as the final few parts need total accuracy !

[Zeeflyboy]

beautiful work, it's all looking so nice and chunky!

[paulus.v]

You can see that this also has stripes where the roughing stepped down on each pass, even though I did a full depth finishing pass. I checked for play in the Y ballnut and ballscrew mounting bearing and all was well. I pushed and pulled the spindle and all seem OK (well, as stiff as it always was anyway). I'll keep an eye on it as the final few parts need total accuracy !

Isn't your softwood spoilboard the problem? Holding that chunk of metal with only four small woodscrews... Just a thought, I don't have experience with similar setups.

I'm following with interest your nice work!

[routercnc]

Thanks Paulus,

All thoughts are welcome. I did wonder if it might move the part but after it was cut out I grabbed it and tried to pull it around on the spoil board but couldn't move it at all. It was pretty solid.
I've cut lots of parts out using this spoilboard method and not seen this result before.
Also before I started the profile cut out I marked around the perimeter with a pen, and the part had not moved relative to this outline.
For the bores I was also only taking 0.02 mm cuts which is very little tool pressure, just taking whispers of metal off, and yet it still seemed to be progressing in the -Y direction by a small fraction each time.

So at the moment I'm assuming this is a new electrical or mechanical problem that has developed. I've put this poor little machine through quite a workout considering it was meant for plywood and balsa wood, so anything is possible. Maybe it has finally figured out it is making it's successor . . .

I also thought about whether I was missing steps on change of direction, maybe somehow the step active high/low setting had changed? Next chance I get in the workshop I'll check that and I'll run some G-code moving the Y axis back and forth various distances and at various feedrates (without load), stopping back against a DTI, and see what happens. Then I'll take it from there, repeating with the spindle on (no load), then some edge cuts, etc. and see if it returns to DTI zero.