Second Post, Second Project, Some Qs

[Tool-n-Around]

OK, so here’s my second cb project. It’s an air filter base and lid for the same automotive induction system in my first post here:

https://cambamcnc.com/forum/index.php?topic=9238.0

I’ve made similar oval filters and cut the polystyrene patterns with hand guided MDF templates on a pin router then cast the filter housing in aluminum using the lost foam method. On this induction system the carbs are too close together for separate oval filters so it requires a single filter for both. The four attached files are the (mostly complete) air filter base and lid. There are a top and bottom to each. I have a couple questions around two-sided machining, tool changes, and tool paths for certain tools.

If you look at the files, you’ll see I put four registration holes in the corners. I was going to mount registration pegs on the waste board and use them to locate the stock while successively running the bottom and top side programs. Whether with registration features like this indicating or other positioning aids, is this how two-sided machining is typically done?

I loaded the GRBL Machine plug in but had to disable/ignor the M6 tool change function because my files wouldn’t run. I only have a router with collet. Is M6 tool changing just for CAT like tooling with defined tooling attributes? Gary was kind enough to recommend this method in the link in post #72. Which I understand.

https://cambamcnc.com/forum/index.php?topic=9238.msg72374#msg72374

I need to make some tooling libraries but other than diameter I’m not sure CamBam is really recognizing tooling attributes. Does it? The topside of the lid requires three tool changes. ¼” bull nose, ¼” end mill, ½” dish cutter.

I’d also like to chamfer the perimeter of the topside of the lid with a ½” diameter 90 degree Vee tool. But it seems CamBam doesn’t drive the tool path off the center of the v-point, but treats it as the outside diameter, even though it is designated as a 90 degree vee. Is that correct? I figure I can either mis-state the diameter and/or the depth to get the chamfer I want but doesn’t seem right. What is usual practice?

Best,
Kelly

[Tool-n-Around]

I exceeded the attachment limit so here are the four files for the lid.

Best,
Kelly

[driedeker]

Take a look at making each tool change another part and use the gcode by part name plugin.
Tooling libraries are a must and yes cam bam does use diameter and tool types example if you drill with a millbit it does spirel and if you then change to a drill it will give you the peck option.
Gble is a limiting factor its for hobby machines in my opinion.

plugin https://cambamcnc.com/forum/index.php?topic=5587.msg44685#msg44685

[dave benson]

HI Kelly

For the 90 beg V tool paths you could try the 'Break Edges' plugin.
It's good to align your CB tool libraries with the sim tool libraries too.
Dave

[Tool-n-Around]

Take a look at making each tool change another part and use the gcode by part name plugin. plugin https://cambamcnc.com/forum/index.php?topic=5587.msg44685#msg44685

The amazing world of plugins. Looks like that one is an automated way of doing what Gary Lucas suggested…….generating separate files for each Part so a (different) tool can be manually changed and set.

Gble is a limiting factor its for hobby machines in my opinion.

I’ve gathered this from other sources. Hopefully someday I’ll out grow it, but for now, it’s what I have and my CNC needs at this point are modest.

Tooling libraries are a must and yes cam bam does use diameter and tool types example if you drill with a millbit it does spirel and if you then change to a drill it will give you the peck option.

For the 90 beg V tool paths you could try the 'Break Edges' plugin. It's good to align your CB tool libraries with the sim tool libraries too.

Ahh, another plug in. I’ll look that one over too.

I’m sure my limited understanding of CamBam and all else at this point is a contributing factor, so please set me straight if I don’t have it right in the following. Perhaps it can also be a matter of the type of MOP operation selected. It seems that MOP doesn’t really care about any tool characteristic other than diameter. In this instance, I entered the tool characteristics of a ½” diameter 90 degree v-cutter then selected profile as the operation on the polyline defining the outer perimeter of the air filter lid. But for that machine op, it will never cut a chamfer at any depth if it only sees the tool by the OD. If I set the tool diameter at something very small (say .00001) and set the desired chamfer depth, it cuts the chamfer on the Polyline using the Profile MOP. Looks like Engrave could be a more appropriate MOP for chamfering and just select the perimeter Polyline and set the desired chamfer depth.

Best,
Kelly

[driedeker]

haha there is a chamfer plugin as well. its a good source of ways to do stuff easy. fillet-chamfer  http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/fillet-chamfer.html
take a look at what we got http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/plugin_menu.html

[Tool-n-Around]

...haha there is a chamfer plugin as well. its a good source of ways to do stuff easy. fillet-chamfer  http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/fillet-chamfer.html take a look at what we got http://www.atelier-des-fougeres.fr/Cambam/Aide/Plugins/plugin_menu.html

I have installed and used a couple plugins but this morning I spent some time looking at what is available and reading about their function. Wow that's quite the list. I saw several that I wished I had downloaded before my last drawing projects. With a better awareness of what's available, I won't hesitate to add them as needed.

Best,
Kelly

[dh42]

Hello

If you look at the files, you’ll see I put four registration holes in the corners. I was going to mount registration pegs on the waste board and use them to locate the stock while successively running the bottom and top side programs. Whether with registration features like this indicating or other positioning aids, is this how two-sided machining is typically done?

Only 2 pins aligned on X or Y axis should be sufficient ..

It's 3D machining, but the workflow is the same for the two-sided machining. (sorry, in French, but there is photos and videos)

http://www.metabricoleur.com/t6747p25-aspirateur-a-copeaux-chariot-v2#120961

http://www.atelier-des-fougeres.fr/Cambam/Aide_V1/tutorials/Usinage3D_2.html

with 2D + 3D machining
http://www.metabricoleur.com/t7986-encore-un-nouveau-systeme-d-aspiration#144064

++
David

[Tool-n-Around]

I cut the air filter patterns today. These are foam patterns to be cast in aluminum via lost foam method. Everything came off well except on the first run, the 2 1/2" vacuum hose shifted, activated the z limit switch, and stopped the program due to soft limit error. For the life of me, I couldn't get the controller out of idle state afterward. I ended up having to shut down, re-home, dial in the work origin, and start the program again. I did break the parts/MOPs up as tool changes were required. The top of the lid required four tools; the rest between one and three. Many thanks for all the help. Nice to have good results.......keeps the learning enthusiasm high.

Best,
Kelly

[lloydsp]

Congratulations, Kelly!  The parts look great.  You're getting a 'handle' on this, now.

CB is probably the second most-useful software product I own, short only of Word.

Lloyd

[dave benson]

That's an excellent result Kelly, seeing the top and bottom assembled
on the Intake put a smile on my dial.

[Tool-n-Around]

Thanks fellas. Not sure I would have gotten there without your help but feeling much more confident and comfortable now and have used it for many related small tasks.

I discovered many opportunities for improvement on my router hardware. I realize it's a hobby rig but I was actually very disappointed with a number of things on the hardware. I think the linear motion hardware is ok, but the ability to actually realize the potential positional accuracy is quite low. The plasma table under under the spoil board is so horribly out of square it's near impossible to mount the rail/gantry system squarely. Best I could get was .015" over 18". I'm not satisfied with that. The provisions for mounting the spoil board were poorly thought through. The z-axis and router mount unnecessarily conceded a lot of rigidity. Not a big deal for cutting foam, but will be for harder materials. The z-axis must be disassembled to remove the router mount. The stepper and homing switch cables are unshielded (and the related EMI issues took several days from me) and will need to be replaced, and about a half a dozen other annoying things.

I have a fairly generous available envelop for my typical projects and will set up a few work locations and a vice at different table locations, but also need to test the accuracy and repeatability of the homing switches

It's all correctable and I will do so in time. I've found the state of tune of one's equipment always says something about the owner. I guess it's like any other machine in regard to needing to be set up and dialed in properly but the provisions for doing so could be much better.

On CAM software, I originally thought I'd bite the bullet and learn and become proficient in solid modeling and related CAM packages but I was wrong on that......I suspect 90%+ of my near term needs can probably be met with CamBam and it's much quicker and easier to learn and perform those tasks with CamBam. I've never experienced a user forum as responsive and helpful as this one. By comparison, the support from the machine manufacture and that forum was Nil. Not sure I would have gotten there without the post processor mod that Dave wrote.......it just works.

Best,
Kelly

[Garyhlucas]

Kelly,
Automation Direct has some high precision limit switches for fairly low prices. Accuracy in microns.

[dave benson]

Hi Kelly

I simulated the Gcode from both files, It's ok.
with PP's once you have one that works, it's a set and forget thing.
You'll have plenty of problems everywhere else in the process but not the PP.
So the Gcode is complete (using your PP) and runs on the sims (I also checked it by hand), depending on
how you have your homing and soft limits configured one of the files would be outside the machines homing
position or soft limits setting on your machine.

I searched around the interwebs and found a video of a young man with the same
machine and Gcode sender, he explains the Lower left hand corner convention
and at the machine homes it (see where the switches are) then go's to the work co-ordinates
and explains the software limits in relation to the placement of the homing switches (it makes a difference).
I would have downloaded UGS from the manufacturers website but my anti virus quarantined it
as a virus, and so can't help directly.

https://www.youtube.com/watch?v=ElzJ1Qhz4WE
This young man’s machine and UGS is set up as I would expect it to be.
This follows the convention of the machine co-ordinates (0,0,0) being the same as lower left hand
 drawing = 0,0,0.

In the second video (he waffles a bit) but  sets up the soft limits and in real time uses the machine to find the values.
and explains that the values will be different (negative numbers) depending on how the stepper motors are wired.
https://www.youtube.com/watch?v=Klrjdu6tPMc
Hope this helps.

Dave

[Tool-n-Around]

Just wanted to update the thread. I did successfully cast the filter base and lid from the cnc'd lost foam patterns described above. The whole blow-by-blow is here at the casting forum:

http://forums.thehomefoundry.org/index.php?threads/automotive-intake-manifold-%E2%80%93-boss-302-independent-runner.1692/page-5#post-41168

.......but I attached a couple pictures below of the machined castings. I just need to splice a filter element together and it's done. Thanks again to all who  assisted. It was greatly appreciated and I'm off making all kinds of things now.

Best,
Kelly