Author Topic: Going over to the dark (CNC) side!  (Read 36816 times)

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #315 on: October 28, 2021, 08:25:01 AM »
Yes it seemed quite happy at those sort of rates so will try something a little faster next time, as I'm on the free version of F360 which uses the feed speed as the rapid any increase in feed is worth while. You may also have spotted that I have the stay down set longer than default and at 70% which combined with being able to set the non engaged feed rate helps that is why you can see the feeds on the screen change eg 510 cutting and 800 return.

Thanks for the screen shots Mike I'll download it and have a play. I'm not sure on out machines what will give up first as the load goes up, the cutter, get excess chatter or something else breaks.

Yes it's a press tool and Mike is close, just the wrong part of the face ;)  I'll leave it to Graham if he wants to say what it is at the moment.

Online Vixen

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Re: Going over to the dark (CNC) side!
« Reply #316 on: October 28, 2021, 12:13:36 PM »

Yes it's a press tool and Mike is close, just the wrong part of the face ;)  I'll leave it to Graham if he wants to say what it is at the moment.

OK, Iwill try again. It's a press tool for making mustache curling tongs.  :help:

FS Wizard is a very comprehensive feed/ speeds calculater. To appreciate what it can do, You need to play around with the inputs and observe the calculated result. What it does not do is to tell you when you are asking too much or if something will break. You may need to buy the Pro version for that.  Alternatively: start with a low feedrate (25% ??) and creep up from there.

Mike
It is the journey that matters, not the destination

Oh! sod the journey, lets hit the bar and pool instead.

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #317 on: October 28, 2021, 12:53:48 PM »
You are getting closer.

I did not see mention of coolant or air on those screen shots which may also make a difference.

Online Alyn Foundry

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Re: Going over to the dark (CNC) side!
« Reply #318 on: October 28, 2021, 02:40:32 PM »
Eye cannot put a face on the current project Jason. My lips are sealed. Obviously you nose what itís for, I presume Iíll be ear ring from you soon?  :)

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #319 on: October 28, 2021, 03:03:22 PM »
It's all crystal clear to me  :-X

Should be in the post tomorrow.

Online crueby

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Re: Going over to the dark (CNC) side!
« Reply #320 on: October 28, 2021, 03:51:41 PM »
Eye cannot put a face on the current project Jason. My lips are sealed. Obviously you nose what itís for, I presume Iíll be ear ring from you soon?  :)
Hmmm.... You are building a mechanical Capt. Jack Sparrow! 

Offline kvom

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Re: Going over to the dark (CNC) side!
« Reply #321 on: October 29, 2021, 10:18:09 AM »
Width of cut is not a factor in chip load, so no surprise that the three calculations are the same.

Endmills for aluminum typically have at most 3 flutes to provide chip clearance, hence are weaker than endmills with the same diameter and more flutes.  For steel my default tool is 1/2" 4 flute.

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #322 on: October 29, 2021, 10:46:14 AM »
I would have though the effect of chip thinning would mean the actual true chip load increases as the width of cut goes up. For example the thickness of chip as the cutting edge exits at 0.1D will be a lot less than at say 0.3D. And it is not until you get to 0.5D that the thickness of the chip cut is the actual feed per tooth.

Offline kvom

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Re: Going over to the dark (CNC) side!
« Reply #323 on: October 29, 2021, 03:01:47 PM »
Chip load is rather theoretical as it's just a function of RPM, feed rate, and flute count.

What you want to optimize is material removal rate while respecting SFM.

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #324 on: November 27, 2021, 07:12:43 PM »
A bit more peeling steel this week.

Started with a 2" dia piece of EN1A (230M07) steel and did most of the work on the CNC. The initial adaptive and contour around the main shape was done with an over length 8mm dia 3 flute cutter as that was the smallest I could find with 30mm long flutes as the sides are 27mm tall. With the whole part being 32mm I also had to feed a bit slower due to 35mm of tool stickout from the collet to stop any chatter.

Then change to a 4mm 3-flute to do a second adaptive around the spigots as the gap was too small for anything larger and then the same tool to contour the spigots.

A couple of ctr drill holes to clock in when boring on the lathe and while I was at it 2.1mm tapping holes for the M2.5 fixings that will hold it to te entablature (part is being machined upside down)


Then I did the Entablature from some 5mm thick EN3. Adaptive with a 6mm 3-flute then contours with a 4mm 3-flute to get into the corners.


Before removing the part from the machine I tried the cylinder, it felt like it would be a press fit which was a bit tighter than I wanted so I tweaked the contour to think it was using a 3.98mm dia cutter and ran it again, this effectively took 0.01mm off the face of the two holes and that was just enough to make it a push fit that assembles by hand yet won't drop off.

I also did the cam while I was at it but did not bother to film that.

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #325 on: December 21, 2021, 03:58:56 PM »
I finally had reason to use the engraving cutters I bought almost 18months back see this post

https://www.modelenginemaker.com/index.php/topic,8882.msg224230.html#msg224230

A good friend who is into building model ships finally finished one and as well as asking me to make the display cabinet also mentioned a plaque to go with it and I said I would see what I could do.

Size was to be no more than 80mm which dictated the font size which ended up being 2.5mm high for the lower two lines and 4mm for the top one. I used the pointed single flute 60degree cutter and as the width of the lines meant it was not going in much deeper than 0.12mm the actual largest diameter was in the region of 0.1mm which meant a fairly slow feed of 50mm/min with it spinning at my max of 5000rpm to try and not damage the cutter.

As the DOC was so shallow I took a 0.2mm skim off the top of the plate first with a 63mm face mill fitted with inserts intended for non ferrous to ensure the cuts were all the same depth from the top of the work.

I'm quite pleased with how it came out, run time was a bit slow as using the free F360 combined with a slow feed rate meant the rapids were rather sluggish too but I was able to leave the machine to it and get on with other things while it did it's stuff.



I also did a bed plate for the next engine from a block of cast iron at the weekend, adaptive with a 6mm di a cutter 6mm x 0.6mm cuts and finish 3D contour with a 4mm dia cutter with 1mm corner radius, 0.2mm stepdown as all the verticals have 3deg "draft" angle. Finish is good enough  to go straight to paint.


Online Alyn Foundry

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Re: Going over to the dark (CNC) side!
« Reply #326 on: January 02, 2022, 03:21:51 PM »
With the excesses of Christmas and the new year over and done, I ventured out to the workshop.
Armed with the little package that Jason had very kindly sent me a month or so ago. Iím guessing it took me way less time to make my parts than it did to make the tools.

Some Silver soldering, pickling, and polishing later and beholdÖ. A ď highly ď styalised ď Eye of Ra ď

Made from 2 mm 316 Stainless Steel, which still needs to be polished further it forms an integral part for my latest ď top secret ď project.

Thanks again Jason.  :ThumbsUp:

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #327 on: January 02, 2022, 03:52:43 PM »
That looks to have turned out well, now get a move on with the rest so I don't have to worry about letting the secret out :-X :-X :-X

Middle photo has certainly replicated Ra's eye well

Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #328 on: April 24, 2022, 07:39:20 AM »
Bit more into the dark brown side yesterday

To avoid the F360 simulation screen turning red with so many collision markers I had to set quite a bit of stick out for the 4mm ball ended cutter, 115mm to be exact :o



But I managed to get the machining done without breaking any tools. Quite a marathon session starting at 8.30 in the morning and finishing about 6.00pm. Luckily I could just leave the machine to it and get on with other things, just popping back into the workshop when another tool path needed to be started or tool changed from roughing to finishing.



Core box is next on the list so the casting comes out hollow and with some windows in it.





Offline Jasonb

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Re: Going over to the dark (CNC) side!
« Reply #329 on: April 28, 2022, 08:24:11 PM »
Both halves of the core box are now done along with the bearing caps, hopefully on their way to the foundry tomorrow