Machining Time

Not enough info. Cutter diameter x feed rate is a start.

ijust want the equation not calculation sry it's my fault expression

OK, good luck.

I'd just machine one and see how long it took. I'm all out of equations.

Ed, the problem you run into is setup time. sure, if this is a CNC then the actual machining time is going to be pretty much a fixed and predictable quantity, but the guy mounting the stock in the machine and getting it running true is going to be a HUGE variable. He might be hung over or didn't get enough sleep or just feeling like crap that day. Any time you have a human element in the equation, the only way to truly arrive at a real number is empirically over several days and multiple operators.

Rorschach -- I left out mention of setup time as well as the cost factors because the one thing fairly clear from the OP's initial question was that it was confined to the issue of actual machining run time. So it was reasonable to assume from the simple minded manner in which he posed his question that discussion of additional cost factors normally addressed in the estimating process would likely just confuse him.

MoronicBumble mentioned that the vast majority of washers are made by other high volume fab processes. But there are a few specially machined precision washers made from either alloys that are too costly to punch due to the material limitations of practical die materials or which have tolerance requirements that require machining or even grinding for flatness and parallelism.

One such easy to visualize application is the common slitting saw arbor. The arbor and the stepped clamping washer are machined to the same diameter and have similar contours. So they can be machined from the same piece of bar stock in the same machine setup, the washer likely being done first and the arbor body second (but not necessarily, if the shank is a small morse taper). A machined clamping washer is needed because the required contour and flatness to avoid distortion of the saw blade is beyond what can be done by stamping.

The determination by a machine shop of whether to do the two parts sequentially on the same setup or do them in two different setups would be a nice scholastic exercise in evaluating many fine points of the machining process to determine which of the two approaches has the shortest cycle time as well as economies of motion involved in doing the second setup, which will have many of the same tools and settings as the first.

All of these factors apply whether the machine tool selected is DNC, CNC, screw machine, turret manual lathe or engine lathe. The same can be said of a variety of materials. For the student to study all variables would itself be a good term paper project for the advanced junior college vocational student.

Ed Weldon

oh no sry for disturb iam just new to the sight and iconfuse idon't know how it's going

This is actually a great place for joking! (Here, we might joke about spelling "thanks" "thnx" and for leaving out punctuation. Although we understand that English is not your first language, you certainly know how to spell "thanks" correctly, and were taught how to punctuate, space words, and capitalize. If you choose to spell incorrectly and punctuate incorrectly so aggressively, then we assume that you believe your time is more valuable than ours. For you, we assume, it is perfectly OK to make us struggle to figure out what you mean, because your idiotic presentation technique apparently saves you time. We might not think of you as so much of a "cuty" as you think we would.)

There is no universal formula for calculating the machining time for a piece, because that time is dependent upon the machine doing the work and the process used. Although a washer would rarely be made on a lathe, one can imagine starting with a piece of bar stock, and first machining the OD to the intended OD of the washer. Then one could drill (and then bore to size, if required) the ID. Then, a cutoff tool could be used to cut the washer to thickness. However, 99.9999999% of the washers made are not made by this process. Virtually all washers are stamped from sheet, with a "machining" time per washer being in the millisecond and sub-millisecond range.

To be taken seriously, here or elsewhere, you would need to describe the process you have in mind, and provide a rationale for how you would approach the problem. Why, for example, not simply stamp the washers? Is there a precision or size constraint involved?) If you take some time to envision the process, then (assuming you have at least a the math ability of a 12 year-old) you can easily come up with the time required for a particular machine operation, given the feed rate practical for the particular machine, material, and workpiece size -- no "formula" required.

In the real world, if you take the time to think the problem through, you will find that the "formula" suggests itself, and that the actual throughput will depend, typically, on many things besides feed rate, diameter, etc.

per one washer the answer would be:

number of produced Washers per time produced all set against one washer produced equals ??? time!

that shall be it!

An Engineer

Mate, give up you're talking either to a machine, an Alien or a prankster.

... or a poorly educated teenager!

Unless these are MS washers, why would you machine them? Most production washers are produced with a N/C punch press.

The materiel being machined is paramount. 303 Stainless machines differently than Monel which machines differently than Aluminum.

The lubricant is secondary to the materiel and will be dictated by the materiel, machine process (feeds and speeds), quality of the cutting tools (some job-shoppers try to use only mild tool steel), etc. The temperature of the coolant is critical. A given tool will sometimes produce a better cut, when warm then, when cold with a specific coolant.

The most important factor is the skill of the machinist and his knowledge of the machine and machining operation. A machinist with 20 years experience on a mill may be a fish-out-of-water on a lathe. Is there an allowance for a realization curve?

How about 100 washers per second?

Washers are commercially produced using a die that punches the small hole first and then the material advances and and the o.d. is punched. Many pieces are punched in one operation.

The base material is sheet metal that is of the correct thickness for that size washer.

The press is set running and the material is fed in automatically.

The equation for this process is n*p/m.

Of course the more required per punch and the larger the washer the greater the force required.

The equation for this is n*p*prm*th = f

How about posting the exact question the dr gave you? Include ALL information. You have not given us any idea of the information you have to work with. It could be a question like "If a process produces 1200 pieces per hour, how long does it take to produce one piece?".

You gave an equation machining time=∏dl/v.f=T/np) WHERE NP=no.of pieces cut per one sec. If NP= pieces per second, then 1/NP= seconds per piece. In that case 1/NP=∏dl*T/v*f, if the equation you gave is correct.

Then you are Screwed Wash ered up.

1) Why do you think workpiece length (l) has anything to do with this?

If cutting the washer off the bar is the longest operation, You need the radius of the washer, not l;

2) What makes you think that l=f again? You are saying that the washers "length" is the machine tool feed rate? So you are making 0.010" thick (thin!) washers in the case of say steel?

3) Your presumption that one washer is one revolution? t ultimately = 1/rpm is absurd.

Presuming 300 rpm, you are saying the process will take 1/300 th of a minute?

Hmm 1 minute = 60 seconds; 60 seconds divided by 300= 0.20 seconds?

You are going to drill a hole, cut off simultaneously from od>in while drill is in ID going into part in 0.20 seconds? How you going to do that?

What is the longest operation?

At the feed rate for the material in inches per rev, how many revs?

At the RPM for the machine for the tool material combination, How many seconds will those revs be?

Now, how many other nonsimultaneous cutting operations are needed.

What about the hole?

What about stock removal of the OD?

This is a process , not a guess exercise. What are the steps to make the washer. (how many steps are there?) How much time for each? How do you figure that? Add them all up.

Milo

To cutyengineer: The best answer is way back from Ed Weldon. He's actually giving you too much information. What you are wanting is an equation that requires no thought given to the process. Ed's answer is empathetic but in a way robbing you of an education in "thinking". That is the real value of education -- not being able to quote equations or facts by rote. This is part of becoming a real engineer, scientist, or whatever your career goal is. Only... if you've chosen the financial world, for God's sake, if you do learn to think, you'll either help right a wayward industry, or you'll probably decide (after thinking) that another field is more ethical.