03-13-2015, 02:33 PM (This post was last modified: 03-13-2015, 02:34 PM by aRM.)
(03-09-2015, 01:56 PM)DaveH Wrote: aRM
Thanks,
[b]My only problem with Walter is they don't have an office here in South Africa. After sales could be troublesome maybe Iscar, Sandvik Coromant, Kennametal might be a better option if they have something similar the the Walter F4041.
I'm not trying to do Walter out of a sale - you have to look at it from your point of view.
DaveH
Hey Dave
I am a bit surprised at U having been so long in the business, U could not find Walter locally ??? Maybe, just maybe, they were not around in Your time of business.
Well I have news for U, Sir.
Spectra Carbide Tooling in PE are the local distributors for Walter and I have been talking to the nice ladies there. This info was from the Walter web site.
So if U ever decide to change Inserts, I will give U their contact details !!!
aRM
03-13-2015, 03:24 PM (This post was last modified: 03-13-2015, 03:26 PM by aRM.)
(03-11-2015, 04:22 PM)PixMan Wrote: Everything you just listed fits together and would be the PERFECT for the task!
If they'll ship to you and you can afford the investment, you'll have zero regrets.
That grade isn't ideal for austenitic (300 series, non-magnetic) stainless steel but at lower speeds it would work. Being in the knife business I would guess that you're using the ferritic/martensitic stainless steels known over here as 410, 410, 430 & 440C or 440F. The grade is perfect for those too.
Best of luck,
Ken
Hello there KEN
Sorry about the delay in responding. Been doing my homework in the interim.
I am a bit chuffed at the moment, (is an understatement) !!!
Like I told DAVE, Walter does have a local distributor and we have Ordered our F4080 and the ODMT Inserts to go with. They promised Delivery in about a week. We can wait, excitedly, hopefully.
Heck Man, U one knowledgeable Machinist as well, seeing U talk hardening Steels fluently !!!
440C has long been the Industry standard. Whilst we are lucky in that we are between U Guys, the Europeans and the Asians, we have a wide choice of Steels from the best in the business. We have used ATS34 from HITACHI, JAPAN which is good for Collector-Grade Knives. Our current well-used N690 from Bohler is the Austrian equivalent of 440c. With (cryogenic) Liquid nitrogen quenching we have achieved 65 Rockwell, but keep this figure lower for ease of Customer sharpening and reducing the overall brittleness at the same time. (Without gloating, we are maybe one of the rare Knifemakers in the Country owning our own full-sized ROCKWELL Hardness Tester.) Bohler has, from about a year or two, also launched their own CPM Graded ELMAX which suddenly shot into fame in the States and is used by U Guys top production Knife companies. They are all ranting and raving about this steel.
CPM - Crucible Powder Metallurgy Steels are all the rave in the States now-a-days. There's CPM 3-V, CPM 4-V, CPM S30V, CPMS35-VN, CPM 154 (Old 154CM) etc which outdo any of the older popular Grades because of newer, better research and manufacturing methods. Heck Man, there's even CPM D2 !!
What more could one need !!! Need to stop now before this gets too far.
'Tis been good conversing with an erudite Machinist for a change.
LORD BLESS
aRM
Hi aRM,
I wasn't saying I could not get a Walter tool locally, Toolquip would probably get me one with pleasure and I would usually pay handsomely for the privilege.
I have always found it better to deal direct with the brand company if possible.
The next best thing is to find a local company with a Brand agency - like the one you have found in PE, provided they don't have 200 agencies.
I think that PE company should be fine.
DaveH
Now tell me more about your machine and the material condition so we can discuss the parameters for running the cutter. Is that a CNC controlled machine with servo or stepper motor driven ball screws? I sure hope so, for best tool performance.
For the steels you are face milling, you'll find good info for cutting speeds and feed rates within the Walter catalog. I'm only familiar with the US/Canada version of their website, but on that Walter website you can download the catalogs, which can be viewed with ease if your computer has Microsoft Silverlight loaded. It also can be viewed on the website, but is slower that way. They also have apps for smartphones and tablets which work well.
Do you program the machine or run by "hand"?
Using my version of the catalog I get cutting speeds in "surface feet per minute", you might use "meters per minute". I'll try to translate.
For a high end tool steel that's at 400Hb (Brinell hardness), which I think is what you were having trouble with, the cutting speed for grade WKP25S is 300 sfm, or 91.44 m/min. That's to be used for a 1:1 to a 1:2 width of cut to cutter diameter ratio. The cutting speed can be increased by 20% if the width of cut with the 50mm cutter is reduced below 10mm wide. At a cutting speed of 91.44 m/min, your spindle rpm for a 50mm cutter is 582 rpm. That should be at the bottom end of your machine's "high range" for spindle speed, so use the low range and have more torque available.
The insert grade and coating determines cutting speed, the insert edge prep, approach angle, entry angle and chipbreaker design all factor in feed rate per tooth. For cutting with the grade WKP25S and geometry (chipbreaker) D57 at full width of cut, the maximum depth of cut is .1574", or 4mm. I don't think you'll be able to exceed 2.5mm with a 2HP spindle. The book is recommending .012" (0.3mm) feed per tooth, times 3 inserts = .9mm per rev, time 582 rpm = 177.4 mm/min feed. I apologize, as I don't know what units your machine runs, so that would be about 20.9 in/min. feed. It sounds somewhat high, but that's what those inserts can handle. You should see significant increase in tool life over anything you've tried thus far.
The HP pull of the cut depends upon depth of cut and the insert geometry, we know it's a 45º approach angle. I would hope you have ball screw drives and can "climb" mill with the cutter. Using the Walter Machining Calculator and entering those parameters for 25mm wide cut, 45º approach angle, a 1,5mm depth of cut and that feed rate, it pulls a little over 2HP but you actually get enough torque to do it in low range.
As for buying tooling over there, I don't know how it works there but here it's best to buy through a distributor who is authorized by the manufacturer. The distributors get a discount that allows them to make a profit selling up to (and rarely, over) the suggested list price. If the manufacturer sells direct to the end user for a discount, they wouldn't have any distributors for long. It's always better to have multiple outlets for your goods, so more end users can have access to the products and support them.
03-18-2015, 02:59 PM (This post was last modified: 03-18-2015, 03:02 PM by aRM.
Edit Reason: rectify errors
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KEN
U have this Machining down to a fine art in total contrast to our plod and plough, learn-by-mistakes, break-bits, self-teach methodology.
Let's start where U commenced.
No Sir, we don't have a CNC controlled Machine. However, we are permitted to dream !!!
Here's pics of our machine ............all over the shore !!!
At the outset, permit us to be open and frank - we know zilch, zero, absolutely nothing about Speeds and Feeds. U see that pic of the pulley setting, we inserted that so's U will accept it, that, well it practically remains there permanently !!! Yup, what we do practise is using the Lows for High Torque and the Highs for finishing cuts. The Power Switch has another two settings for Forward Low/High and Reverse Low/High which gives us a fairly wide spectrum of speeds to work with.
But when U rattle on about FEED RATE with Depth of Cut and the Power of the Machine being able to cope with the given insert geometry, then here again, we totally accept Your given parameters, but sad to say, we are totally unskilled, inexperienced and therefore unable to perfectly implement Your lucid practical advices. Yes, we would definitely very discreetly use our power feed on the Low High torque Speeds, as U have suggested, but here again, having learnt the hard way, would hear and act on the reaction of the cutting tool and the vibration of the machine to judge and estimate whether any of these settings need be increased or lowered. Generally, we would hesitate to take serious 3mm or 4mm cuts on our machine and usually commence with 1 - 1.5mm cuts, more on the side of caution.
Yeah, yeah, we hear U say "these Guys must be plumb crazy" !!! But truth be told, like the mill we have only recently learned how to Thread, taper turn, Knurl, part etc on our lathe. Nothing to be ashamed of. Just that we have unfortunately not had any formal training, except having avidly read what we could garner on these subjects, and have had to teach ourselves and learn along the way from Experts like Your kind self.
Walter do indeed have a massive catalogue, which we have downloaded and extracted hard copies of the sections U referred to specifically. Looking at our Spindle Speed plaque on the machine, we reckon we would be about right at 210/420 RPM for this cutter ???
We do appreciate the tremendous inputs U have made and must sincerely state that we have indeed benefitted hugely from Your writings and recommendations. Your "pearls" have not fallen on deaf ears. We will make a concerted effort to grapple and unravel this SPEED FEED quandary which has been eluding us.
It gives the basic concepts of vertical milling mainly for bench and smaller machines, smaller than the one you have and only for HSS and carbide end mills and slot mills. However the basic principles still apply to your machine. Just remember it does not cover insert milling cutters, nor does it apply to the use thereof.
DaveH
Dave, you missed one other reason for cutter breakage. CAC (cheap ass cutter). I broke one of my dovetail cutters the other day due to that reason. Good write up!
Yep, cheap cutters are rarely worth it. Unless of course one can get good branded cutters cheap - now that is a different story.
Cheap inserts are just the same.
DaveH
That's a pretty good machine there aRM, no reason to think you won't love that cutter when you get it and use it.
You can't climb mill with it, but as long as you have at least 2/3rds of the cutter diameter engaged you should be OK with that. For less than that, be sure your cutter is to the right side of cutting path and workpiece to its left (conventional milling.)
Any idea when the new cutter and inserts will show up?
