New machine not doing what it is ment to.
Discussion
DSLiverpool said:
Gents I suggest we buckle an alloy and call the OP`s company to get it fixed and whilst on the phone we ask if they do diamond finishes without the marks 
The trick old chap is in the marketing. 'NEW! We can now supply alloys in the latest speckled finish! No extra charge!'
Whooh whooh whooh, calm down folks, I'm here, did try and post a reply on Weds night but PH appeared to be broken.
Ok, so Tuesday he was late arriving, but once here he checked that my lads had set the machine, probe and tip up correctly, which they had, all the offsets were good, he checked that they were optimising the data ok, no problems there.
He then plotted and cut 2 alloy wheels, and at last agreed that something was not right.
Back Weds am to continue looking, he just kept going over and over the same things, he upped the speeds, slowed the speeds, changed the tips, still no improvement at all.
He then made some phone calls to another company which has 4 lathes, 2 of which are the same as ours, and all of them use the same diamond carbide tips.
They said the tips need "bedding" in from new, up to 50 cuts, they said when they change a tip they put a scrap alloy in and do a min of 50 0.2 cuts, this dresses the tip to provide a good finish.
So, a scrap wheel was found, and 50+ cuts were made, I knew it probably was not this, but keen to try just about anything, I'll let you guys guess the rest.
The trainer, and I use that term loosely was kicked halfway back to Yorkshire, with instructions that its sorted with 7 days or the s
te really will hit the fan.
There is a massive trade show at the NEC next week, 3 day event, and I know these guys have a big trade stand there, if any body is going then come say hi, I will be the one standing right by their stand, wearing a t-shirt with "Don't buy this lathe, its not fit for purpose" printed all over it.
Maybe that will get results, or me thrown out by security.
Sorry not better news folks, we will either get to the bottom of it or the machine will be returned pronto.
Ok, so Tuesday he was late arriving, but once here he checked that my lads had set the machine, probe and tip up correctly, which they had, all the offsets were good, he checked that they were optimising the data ok, no problems there.
He then plotted and cut 2 alloy wheels, and at last agreed that something was not right.
Back Weds am to continue looking, he just kept going over and over the same things, he upped the speeds, slowed the speeds, changed the tips, still no improvement at all.
He then made some phone calls to another company which has 4 lathes, 2 of which are the same as ours, and all of them use the same diamond carbide tips.
They said the tips need "bedding" in from new, up to 50 cuts, they said when they change a tip they put a scrap alloy in and do a min of 50 0.2 cuts, this dresses the tip to provide a good finish.
So, a scrap wheel was found, and 50+ cuts were made, I knew it probably was not this, but keen to try just about anything, I'll let you guys guess the rest.
The trainer, and I use that term loosely was kicked halfway back to Yorkshire, with instructions that its sorted with 7 days or the s
te really will hit the fan.There is a massive trade show at the NEC next week, 3 day event, and I know these guys have a big trade stand there, if any body is going then come say hi, I will be the one standing right by their stand, wearing a t-shirt with "Don't buy this lathe, its not fit for purpose" printed all over it.
Maybe that will get results, or me thrown out by security.
Sorry not better news folks, we will either get to the bottom of it or the machine will be returned pronto.
do these marks polish out ? are the marks actually pitted ?
I know the trainer has been down, but have you tried turning a wheel with coolant ? I know the training did not use any but personally I would still use some.
hope it gets sorted quickly.
I know the trainer has been down, but have you tried turning a wheel with coolant ? I know the training did not use any but personally I would still use some.
hope it gets sorted quickly.
Edited by familyguy1 on Monday 6th June 09:21
Hi,
What has been done to take into account of the tool post angle? Did you shim the cutter to make sure the cutting tool is presented to the workpiece properly?
Have you tried or are you using cutting fluid? That would help diagnose a rubbing/overheating issue.
As said I'm new to this too and hopefully somebody else can step in but 800rpm max seems a little slow because the surface speed of the wheel will be low due to the size. There are calculations that you can do to see what speed is (unless I'm confusing milling info?)
Tbh most trainers aren't really machinists (I'm not either) so I wouldn't put much hope it him tbh unless he is trained.
This kinda work isn't just pressing buttons and it's done, there's a lot of background info you have to familiarise yourself with too. I've bought a lathe recently and I'm about to get a milling machine so I'm in the same boat.
What has been done to take into account of the tool post angle? Did you shim the cutter to make sure the cutting tool is presented to the workpiece properly?
Have you tried or are you using cutting fluid? That would help diagnose a rubbing/overheating issue.
As said I'm new to this too and hopefully somebody else can step in but 800rpm max seems a little slow because the surface speed of the wheel will be low due to the size. There are calculations that you can do to see what speed is (unless I'm confusing milling info?)
Tbh most trainers aren't really machinists (I'm not either) so I wouldn't put much hope it him tbh unless he is trained.
This kinda work isn't just pressing buttons and it's done, there's a lot of background info you have to familiarise yourself with too. I've bought a lathe recently and I'm about to get a milling machine so I'm in the same boat.
Quattromaster said:
dudleybloke said:
How's the swarf looking? Is it chipping or streaming?
Chips on the small sections of wheel, streams off around the edges. See pic
What else could be happening to the ally to produce this finish?
C'mon'tfk!
The combined brainpower of the PH massive, and we're still wandering around aimlessly... Outsidetheboxthinkingtime.
tumble dryer said:
Quattromaster said:
dudleybloke said:
How's the swarf looking? Is it chipping or streaming?
Chips on the small sections of wheel, streams off around the edges. See picWhat else could be happening to the ally to produce this finish?
C'mon'tfk!
The combined brainpower of the PH massive, and we're still wandering around aimlessly... Outsidetheboxthinkingtime.
Despite it being setup religiously as per the manufacturers instructions, and even with additional coolant filtration being added in by yours truly, somehow some contaminants were still finding their way onto the grinding wheel and leaving fleck marks on the ski bases
Brand new stone, new diamond dressing bit, the works, and nothing sorted it, as a machine it just never worked properly
It wasn't sorted before I left and as far as I know it never was
Sometimes, it's worth just getting a whole new machine rather than trying to chase a ghost
I'm no machinist but I've got my own lathe and done a fair bit of turning...
To my eye (and I'm only looking at this on a phone) it looks like it's tearing rather than cutting. One of the issues I've seen especially with aluminium is I'd you aren't careful you get aluminium build up on the tool tip and that then ruins any hope of a good finish.
I still mostly cut aluminium 'dry' but for precision/finishing I use an aluminium cutting compound (more like a wax actually) on the tip before I start and reasonably regular squirts of WD40 (other people also recommend kerosene) to prevent build up.
To my eye (and I'm only looking at this on a phone) it looks like it's tearing rather than cutting. One of the issues I've seen especially with aluminium is I'd you aren't careful you get aluminium build up on the tool tip and that then ruins any hope of a good finish.
I still mostly cut aluminium 'dry' but for precision/finishing I use an aluminium cutting compound (more like a wax actually) on the tip before I start and reasonably regular squirts of WD40 (other people also recommend kerosene) to prevent build up.
DanSaff said:
As said I'm new to this too and hopefully somebody else can step in but 800rpm max seems a little slow because the surface speed of the wheel will be low due to the size. There are calculations that you can do to see what speed is (unless I'm confusing milling info?)
Assuming a 17" diameter wheel, that gives a circumference of 1.35 metres.Cutting data for PD150 grade, (don't know Si content of Aluminium in Alloys so using 9-14% data)
Cutting speed 600-2500 m/min, so your rpm should be 440-1850rpm. This is at outer edge, the cutting speed will be slower the closer to the centre you go as circumference decreases.
Feed of 0.1-0.5mm
And a depth up to 3mm, so doesn't look too far off.
With everything you tried I'd be looking at tooling, either tool is not in right position, not on centre line or its the tool/insert. As asked before, you are using the right type of holder, positive geo insert would be flat in the holder rather than angled back for clearance.
Doesn't sound like your trainer knows much, I'd have expected him to turn up with proven tooling/wheel to test on your machine and prove to you that everything is correct if he couldn't get it running with your tools and wheels.
Heard a story today about a guy who had a wheel lathe, not sure of make, but he was producing outstanding work, except on a Thursday, and only a Thursday.
They spent almost 3 months trying to work out what was wrong, including setting up webcams so the company who built the lathe in the USA could watch him , still no luck.
It was then discovered that the next unit along from him was a printers, and their biggest machine was just the other side of the wall, I'll let you guess what day of the week they fired it up.
The concrete floors were so thin that the printing press was shaking the lathe, they lifted the lathe and sat it on 10mm rubber washers, problem solved.
Now, we don't have a printers next door, so I know it's not that, lol, but just goes to show how sensitive these machines can be, and as another previous poster said, you sometimes really need to think outside the box.
They spent almost 3 months trying to work out what was wrong, including setting up webcams so the company who built the lathe in the USA could watch him , still no luck.
It was then discovered that the next unit along from him was a printers, and their biggest machine was just the other side of the wall, I'll let you guess what day of the week they fired it up.
The concrete floors were so thin that the printing press was shaking the lathe, they lifted the lathe and sat it on 10mm rubber washers, problem solved.
Now, we don't have a printers next door, so I know it's not that, lol, but just goes to show how sensitive these machines can be, and as another previous poster said, you sometimes really need to think outside the box.
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