Further Adventures with the Sieg KX3 & KX1

About 1hr 41mins machine time plus the changing of tools. Seems a long time but still a lot faster than doing it on the manual mill. removed 44% of the original block though there is still more to be turned to swarf when the other side is hollowed out. Alibre says the block started out at 307g and the finished part will eventually weight 63g.

Just over 100,000 lines of G-code, thank God the CAM writes that for me.

Edited By JasonB on 04/07/2019 20:22:22

Excellent work Jason.

Sadly can't see myself getting up and running before September now

Looks good!

As always I might have done a few things differently, but who's to say I'm right or wrong.

I'm either going to have to upgrade my CAM program or start using Fusion360 so I can get going with adaptive toolpaths.

Andrew

Thanks for the interest chaps,

Andrew I'm always interested in how the more experienced user would have gone about things. There are a couple of things that I will do differently when I do the other half such as see if I can do a finer stepdown on the curved portion under the head flange and also make sure I put the correct stock size in as the last minute change to slightly thicker and +1 mm all round left a few bits that should have been removed, the simulator did show this but I did not spot it

If anyone is going to the Guildford Gala Weekend then I will be there tomorrow only and you can see this part in the flesh plus a few of my recent engines.

Jason, I see you used some cutting fluid for the drilling, fluid or coolant is obviously not required for the milling..?

Its the 5000 rpm that always makes me wonder but I guess cutting aluminium with a 2 flute carbide Alu cutter there is no real benefit, it obviously works well enough dry.

Ron

It's what you can't see that matters. I have not got anything set up yet to clear the chips and/or lubricate.

I am giving the occasional blast with the air gun to clear swarf and brushing on a little paraffin every so often . What I also found works quite well is to hold the brush just in front of the air gun and that clears the swarf and sprays the lubricant at the same time with reasonable size droplets so you don't get a mist. It is just that I can't do both of those and hold the camera at the same time.

Looking at the cutting data from another maker of similar high helix uncoated 2-flute cutters designed for aluminium and non ferrous they give a speed of 7000rpm for a 6mm in aluminium so my 5000rpm max is as near as I can get. The same chart also gives data for a similar type of cut as 1xD high and 0.25 x D deep which equates to 6mm x 1.5mm which is a similar amount of metal removal to my 8.5 x 1. However where I did go quite a bit easier was with the feed rates due to the fact I was using a long series cutter and only have manual swarf clearance and lube so rather than feeding at 900mm/min suggested I went with 300mm/min.

And then there were two

Much the same setup as the other half with the addition of a contour cut to form the reduced diameter spigot on the cam shaft boss that will take the ignition contact so timing can be advanced/retarded. I also remembered that I bought a 4-flute radius corner cutter at the same time as the 2-flute and as it was not taking much off per pass there was no need to worry about swarf clearance so I used that and upped the feed to 500mm/min which cut the time a bit.

Looking good Jason, I bet that saved some time over doing them manual.

Yes, having done a couple the manual way it is certainly quicker, whether it is a satisfying is debatable and certainly not so high on the willy waving scale.

I am impressed with what you are managing to do with your machine. Must stop using the manual mill and get on with the using the KX1 got some Fusion 360 drawing done just need to get the g code done and cut metal.

I'd argue that it's more satisfying and higher up on the willy waving scale. After all in order to produce the part one needs to create the design and be able to use 3D CAD. Then one needs to create the G-code and cutting schemes which requires a proper understanding of speeds and feeds versus depth and width of cut. Fixtures also need to be created that allow the part to be machined without getting in the way of the cutter or chuck.

Andrew

I suppose it depends on how you look at it,

For the manually machined engine crank cases I designed the parts and drew them up in 3D CAD so no difference there. Both design stages will take into account what you have available to make the part with and how you will use those items.

Granted you don't need to produce the G-code but you still need to plan a scheme or machining sequence for the type and order of the manual cuts. Also agree that to get the best out of the CNC machine you need to get feeds, speeds and type of cutting right especially as it is harder to alter things once you pres GO!

Fixtures were still needed to hold the parts as well as many setups on the lathe and mill so they could be manually machined. As for clashing I mentioned above that the tool needed to protrude a certain distance to prevent the collet hitting the work, this would be no different on the manual mill or making sure a boring bar is long enough on the lathe so you don't run the toolpost into the work though the manual methods may not result in such a big bang as it would if you got it wrong on the CNC

As for the waving scale there are a lot who would say doing something manually is a lot higher up the shaft than with CNC but may well have never actually tried it.

I have manual machines and also CNC mills and lathe, I don’t think it really matters how you make a part, the important thing is that you are making something.

There are things you can easily do with a CNC mill that are next to impossible manually. For example, for my current Synchronome-based clock project I have cut a pallet to a mathematically defined profile that gives a "raised cosine" impulse force waveform; and an equi-angular spiral cam. For both the coordinates were calculated and the g code generated in Excel.

Oh dear, the word is out that I have a new Machine. Got a phone call last week to say my Niece had bought a second hand lamp to take to Uni and after repainting it had found the bracket that holds the shade had cracked and would my new toy tool be able to make a replacement?

It was posted to me and after drawing up a suitable replacement that CAM was done to produce the code and a pair of brackets cut from a bit of 2" x 0.5" 6082. All milling done with one of Ketan's 6mm HSS aluminium specific cutters. After cutting apart on the bandsaw the counterbores were added on the lathe at the same time as the waste was turned away. Think it will do the job.

Edited By JasonB on 17/07/2019 20:57:38

Nice job for your niece Jason. Night and day improvement over the cheap plastic original bracket!

Thank's Jeff, I just hope she does not want all the other pivots remade to match!

They turned out nice Jason. Are they single flute cutters? It seems to be cutting very well with swarf flying all over the place! I have bought some solid carbide single flute cutters 3, 4 and 6mm (not Arc) and have yet to try them out on my KX1.

Ian

That is a HSS 2-flute cutter with the steeper angle specifically for aluminium and not coated to help stop swarf sticking. It is also a long series one so could probably be run a bit harder if standard length. ARC do the carbide version too and that does come in standard and long length and like the HSS work well on brass and bronze too.

The only downside with the single flute cutters that I can think of is you have to feed at half the rate of a 2-flute if keeping the chip load and speed the same.

This is another of teh HSS 2-flute sin action on th emanual mill

Nice demo, I've bought HSS cutters from Arc they are top quality, they cut great and leave a super finish. My carbide single flutes will be mainly used to cut plastic.