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Author Topic: Bridgeport Knee Mill Conversion?  (Read 270364 times)

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Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #680 on: January 31, 2018, 02:07:47 AM »
I could try chip control but i cant think of any system that would work apart from a massive enclosure that will not detract the bonus of having a fully open flexible knee mill :) Its got more travel than many VMC's do, a much longer bed at 48" and i sometimes hang stuff over or off the sides ")

Re: Bridgeport Knee Mill Conversion?
« Reply #681 on: January 31, 2018, 07:04:12 AM »
I have seen a shower curtain and rectangular curtain rods used to good effect.
Inexpensive, disposable and removable in about 10 seconds.


Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #682 on: February 01, 2018, 04:32:23 AM »
Learn something every day.

Been messing around with a project, engraved aluminium signs, test subject is 360x80mm.

Testing two setups in Fusion - on the Bridgeport standard and on the high speed head.

Standard has 4 tools reducing in size from 8mm to 1.5mm
High speed has two tools - 5mm and 2mm

Fusion was giving simulation times of 2.34hrs for standard and 2.35 for high speed with ramps, i changed the ramps to plunges and times dropped to 1.18 and 1.20 so a massive waste on ramping down.

I need to check these figures out because it would indicate that i do not need a high speed head at all as the old BP is faster (at 4000rpm) Very odd indeed. I know i reduced the rates on the high-speed as its not 100% rigid being canted out from the spindle but if its the same end result i would be better off using the BP spindle as i have repeatable tooling mount then so no repeated touch-offs.

I'm not sure how successful a 1.5mm three flute HsCo tool will be on the old girl but i have a box of them so can try it :)

Need to crunch my numbers again in HSMAdvisor. Can it be just as simple as faster but less feed-rate due to rigidity vs slower but more aggressive cuts????
Re: Bridgeport Knee Mill Conversion?
« Reply #683 on: February 01, 2018, 06:42:11 AM »
It is all about the MRR. Whatever gets the most material removed in the shortest time assuming the end product is usable.


Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #684 on: February 01, 2018, 06:50:36 AM »
Clearly a lot to learn.

I just tried a 2d Adaptive path with HSM speeds, processing time went up to 2.30hrs for just the first tool (5mm) with thousands of retracts etc, would be hard on the machine i think. Picture attached.


Offline olf20

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Re: Bridgeport Knee Mill Conversion?
« Reply #685 on: February 01, 2018, 07:51:35 AM »
Can you use a roughing tool path, then do the cleanup.
I do this with aluminum projects all the time. I'm making
some award medallions for my grandson. Roughing 1/4 em
then 1/8 for finish and cutout.
olf20 / Bob 
Mach3, Atlas Knee Mill, 4th Axis, VcarvePro, ESS, Super PID.
Been Heating with corn since 1998

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #686 on: February 01, 2018, 07:58:23 AM »
Ah, so you say go for standard path on roughing then 2d adaptive on the cleanup tools??

I'll have a play.....



Edit, nope, 2d adaptive does not have "rest" machining so spends hours cutting air :)

I never thought a simple job would have so many variables.
« Last Edit: February 01, 2018, 08:05:08 AM by Davek0974 »
Re: Bridgeport Knee Mill Conversion?
« Reply #687 on: February 01, 2018, 08:38:28 AM »
Very nice job on the mill conversion Dave, I'm envious of your commitment and dedication.
Also, thanks for prompting me to research Adaptive strategies, namely this in-depth explanation of Adaptive Clearing.

https://nexgencam.com/hsm-tips-tricks/item/understanding-hsmworks-adaptive-clearing-toolpaths

Thanks again,
Russ

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #688 on: February 01, 2018, 08:54:55 AM »
Thanks for the compliment Russ,

I'm only scratching the surface in Fusion. I'll have to print that link as they have done the page in white on black and i can't read that, gives me bad headaches, looks good though.

Offline Davek0974

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Re: Bridgeport Knee Mill Conversion?
« Reply #689 on: February 02, 2018, 05:58:14 AM »
Hmm, this little tester is teaching all sorts of things :)

I change tools to two-flute aluminium ones and stuck to my slower BR head at 4000 rpm, machining time is now down to a staggering 23minutes plus tool-changes

I went for 10mm to hog the bulk out, then Rest machining with 5mm, 3mm, 1.5mm - I think that gives a good step-down in tools, adding the 3mm really took the time down.

Now, what i cant figure out is why not all the letters get machined - two pictures attached, one shows the path on a letter "a" with the 3mm tool, the gap is shown in the last picture at over 2mm but the 1.5mm tool refuses to go there so the gap is left joined?

There is no finishing allowance - all paths are to final size.

Any ideas???