PDA

View Full Version : Machining a large shaft



snapatap
2nd May 2016, 08:30 PM
I have a job on the go at work that is not commercially sensitive, so i thought i might post some photos of it. It is a shaft out of a rock crushing machine. The bar we got in to make it out of is 290mm dia. 1825mm long K1045, weight about 960kg. It will weigh about 450kg when finished. We sent the bar out and had a hole gundrilled about 3/4 the way down the bar and a 2" unc thread thread milled in the end. I got the shaft setup in the lathe friday but got called onto another job so i didn't get any machining done.
362316362317
I started machining this morning. WNMG insert 200M/min, 0.4mm/rev,2.5mm depth of cut. If my calculations are correct i was removing about 1.7Kg of steel a minute.
362318362319
The following photos are taken at roughly 30-45min intervals. i had to stop and change cutting edges and clear the swarf out.
362320362321362322362323
Finished roughing the 1st end, it took about 4hrs. I will rough and finish the other end and then finish this end.
362324
The end in the chuck doesn't have a center in it,so before it took the shaft out of the lathe it setup a steady on the large diameter. I then turned the shaft around and supported the tailstock end in the steady, and drilled a No.8 center in the end. Sorry i forgot to take photos of doing that. Below is a photo of how it was at the end of today. the steady has been pushed up by the chuck because i will need it later. My program for the 2nd end is done, i just have to hit go in the morning. TBC....
362325

welder
2nd May 2016, 08:37 PM
Nice turning at a decent feed rate :2tsup:,
what brand of my machine is that ?

snapatap
2nd May 2016, 08:50 PM
The lathe is a AJAX. It has a FANUC Oi-TC controller on it. It is basically a copy of a MAZAK M5 from the 1980's with a current controller on it. The build quality is very good and its a very rigid machine. The only thing that lets it down is the controller, its really a bit backwards, and it gives me the s#!$ at times.

.RC.
3rd May 2016, 11:20 AM
I am always amazed at people who can program a CNC machine. I have no idea how you tell the machine where to even start as it does not have an eye to know where the workpiece starts and stops. Lathe work would probably not be too hard to get around but milling would do my head in.

Oldneweng
3rd May 2016, 11:44 AM
I am always amazed at people who can program a CNC machine. I have no idea how you tell the machine where to even start as it does not have an eye to know where the workpiece starts and stops. Lathe work would probably not be too hard to get around but milling would do my head in.

I have not had anything to do with CNC for over 30yrs (and then only minimal), but I recall seeing a joystick used to jog the tool into position and then reading the location off the screen. I also recall that punching in 3000rpm instead of 300rpm for machining a brake drum is not a good thing. I am glad I wasn't around that shift.

Dean

YBAF
3rd May 2016, 02:36 PM
HEY! wheres the youtube vid ?

:U

snapatap
3rd May 2016, 08:46 PM
HEY! wheres the youtube vid ?

:U

I took a short video, but i don't want a google account so i wont be putting it on youtube.

RC I will give a bit of a rundown on how i programmed it later. i need to take a few more photos so i can explain it easily.

Today's action:
Roughing the 2nd end
362330362331362332
Finishing the 2nd end. I left 2mm on diameter for finishing. What i do 90% of the time is put a 1mm offset on the finishing tool and take a finishing pass. I then measure the sizes and adjust the offset to get the final size, then run the finish cycle again. I can also adjust the program to allow for taper.
362333362334
Next i machined the relief groove for the thread and setup the steady to help stop the shaft chattering when i cut the thread. I had to swap steadies because the big one was short by about 10mm :~. The thread is 6" 4tpi whitworth and was cut with a full form insert at 180RPM, 18 rough passes and 2 finish passes. Pretty happy it came out perfect with no chatter:U.
362335362336362337
Last thing i got done today was to drill the end so i can bore it out and machine a 2" UNC thread in the end.
362338
TBC....

Oldneweng
4th May 2016, 09:43 PM
You do know that you can upload videos to the forum? Video tab at the top of the page.

Great thread.

Dean

YBAF
5th May 2016, 11:54 AM
You do know that you can upload videos to the forum? Video tab at the top of the page.


HA! he got no excuses now :tvhpy:

simonl
7th May 2016, 08:19 PM
Thanks for posting!

What would a job like this end up costing? I also assume a tonne of 1045 would not be cheap!

Simon