Machining Time..

This Task is Killing ME!!!!...

I wish that there is a guideline on how to calculate machine time.

But the problem right now on the data input. Would like to know any guidelines should I follow.

Current machining process that we have right now is :-
1) Boring
2) Drilling
3) Tapping
4) Threading
5) Milling
6) etc.

I wish to know if there is a guidelines for machining time process.

you need to be more specific.. tough to do without a blueprint.

example.. i can drill a 3/8" hole faster than i can drill a 2" hole... i can drill cold roll steel faster than i can drill stainless steel, i can drill aluminum faster than both..


what your asking, is like me asking you how many fish are in my pond?

I am sure at your labor rates, you can afford to make mistakes.

ha_ahmad84 said:

This Task is Killing ME!!!!...

I wish that there is a guideline on how to calculate machine time.

But the problem right now on the data input. Would like to know any guidelines should I follow.

Current machining process that we have right now is :-
1) Boring
2) Drilling
3) Tapping
4) Threading
5) Milling
6) etc.

I wish to know if there is a guidelines for machining time process.

Click to expand...

Yup there sure is for all that. But if you are that worried about it you shouldn't be machining, cause something always goes wrong, and there isn't an equation for that.

What other profession has a mass of greenhorns seeking self employment during a global recession other than machining? For every shop that closes these days 4 hacks open for business that know as much as our OP about bidding and planning work. Being in Malaysia you have enough of an edge on developed countries, with low labor rates, government subsidies and no environmental regulations. My knowledge is the only edge I have over you and I won't shoot myself in the foot by sharing that.

Pretty simple and a couple easy ways to figure it:

#1 - Time study all of your operations that you are looking to develop a standard time measurement. Lets use drilling as an example - go drill a few tens of thousand holes of various diameters, materials and tooling, then extropolate the missing holes in your time study and you should get within an acceptable time tolerance. Do this for milling, boring, turning, etc as well.

#2 - Buy a good CAM system and it will calculate the times for certain operations once you have done #1 above and entered the data for your machine and processes in the CAM software.

If you and your facility are learning, the you need to ad a time factor into the equation as CNCBRIT has eluded to. Probably a factor of 2X to 10X depending on your level of expertise at the particular task at hand considering all facets of the job such as material, workholding, tooling, individual machine, operator, crashes, broken tooling, coolant, no coolant, etc. Maybe you need to make those exponential factors not multiplicative factors.

Most guys here with a few decades under their belts are still learning and are adjusting their time calculations.

Years ago,when I first started working for a CNC manufacturer, part of my job was doing time estiates for potential customers of our CNC lathes.
I had years of background in precision machining but no clue to figuring times.
Here is what I did:
1) Figure the RPM base on SFM an size of tool or part.
2) Figure the feedrate in inches per minute.
3) Divide the length of cut by the feedrate.
It equals cutting time.
Add rapid time, loading, etc.
The details for all this are on my CNC DVD called "Prep for CNC".
Heinz Putz.

MEPro will calculate times for individual tools and create a detailed cost and time analysis for an entire job as you work.

MEPro

Hi have you completed this task ? Means do you got any idea ?. I am also working something related to this and I have few ideas, but not sure how good it is.

Hi I have a doubt, is feed rate is directly proportional to the MRR ?

RajanM said:

Hi I have a doubt, is feed rate is directly proportional to the MRR ?

Click to expand...

FFS,

Please think about what you ask, ...but I'll give you a tip ;- if it isn't, you are in the wrong trade.

ha_ahmad84 said:

This Task is Killing ME!!!!...

I wish that there is a guideline on how to calculate machine time.

But the problem right now on the data input. Would like to know any guidelines should I follow.

Current machining process that we have right now is :-
1) Boring
2) Drilling
3) Tapping
4) Threading
5) Milling
6) etc.

I wish to know if there is a guidelines for machining time process.

Click to expand...

many cnc have a built in timer and you can zero it and it will tell
1) total time used
2) time machine actually running it does not count M0 or when machine is paused
3) some have graphics simulation and it will estimate time
.
since rapids can take time as well as tool change time and any M0 the machine run timer stops many time estimates are less than actual time used. i record clock time job started and time stopped and use excel to calculate average and note any reasons if over the average time. quite normal for actual time used to be much more than run time or estimated time

Dualkit said:

My knowledge is the only edge I have over you and I won't shoot myself in the foot by sharing that.

Click to expand...

WTF? That's all this forum is. Oh wait, there are other "important" conversations among the regulars.

in any shop there are machinist that offer advice when asked and some offer advice even when not asked. then their are others who share nothing, teach nobody as they worry about loosing job or loosing overtime
.
i had a boss if you did not write work instructions and you did not teach anybody you were not given any pay raises and job ranking was never the highest. this was done to eventually get rid or lay off the secretive not team player types.
.
all the secretive types who thought nobody could do their job, 99.9999% of the time within 1 year after they were replaced often most jobs were done faster after they were gone. thats cause usually a group who share ideals and use the best ideals normally do better than the lone secretive types.
.
even Thomas Edison who had over 1000 patents most were cause he had a group of people working with him. he got his name on patents cause he was the boss not cause he actually invented everything himself. many companies you sign papers any ideals or patents belong to the company not to the individual otherwise you are not hired for the job

I guess this is also directly related to the dark art of quoting...

You work out that it takes 1minute to drill through a part 120mm thick @ 120mm/min. Then you start thinking about how much time your retracts from pecks will take if your machine can rapid at 30M/min, rapids up to 3mm off the part and back down to 1mm from last peck every 10mm of drill depth. Then you realise that if you are drilling 120mm of drill depth you are actually drilling 132mm, rapids excluded. But then you start thinking that to drill through you actually need to go deeper than 120mm because your drill has a 118 deg edge so you add an extra 5mm.

You get a rough guess of 1 1/2 min per hole but you are forgetting how you got to the hole... How long is your travel from toolchange position? What is the distance between your holes? Is your machine reaching it's full 30M/min rapids between pecks? How long does it take to do a toolchange? Then if it is not production you start thinking how long does it take you to put the drill in the holder, load it into the machine,set it's height and check that it is correct. And what happens if the machine has to be attended at all times to check for tool breakage but you need to take a pee every 2 hours.

By this time you are about to throw the print and calculations into the bin and start working on experience But then of course there are the facing,profiling, filling the coolant tank,way oil,digging the chips out of the T slots,going for a pee again, forgetting that the machine is on 50% rapids,loading the part, operations still to consider.

This sounds a lot like a homework question to me. I'm done with my assignment for the day and just got the damn hole drilled by actually doing it and roughly remembering how long it took me for reference if I ever got a similar part again.

I've found turning is a bit easier, 2 axis stuff, to get rough times but all in all experience sure does help.... I can't finish this post off properly,had to take a crap in between so cannot tell you how long it took me in total to type it.

FK said:

WTF? That's all this forum is. Oh wait, there are other "important" conversations among the regulars.

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That's cuz these elementary arithmetic questions are so boring ... at 60 miles an hour, how long does it take Freddie to drive to Lisa's house, which is eleven miles away ?

SeaMoss said:

That's cuz these elementary arithmetic questions are so boring ... at 60 miles an hour, how long does it take Freddie to drive to Lisa's house, which is eleven miles away ?

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20 min, because he stopped off to buy her a bunch of flowers on the way. maybe more because he realised that the flower shop doesn't accept cards so he had to go withdraw cash first.

just record actual machining times used. once you do job 100 times the average time is far more accurate than any estimated time
.
by the way i record rework or remaking any scrapped parts. if job takes 10 hours cause you had to remake a scrapped part it took 10 hours even if average is 5 hours. often the remaking scrap parts will increase average time per 100 parts to 5.5 hours until many hundreds more are make with no scrap parts.
.
not unusual for going slower and not scrapping parts to be faster in the long run

SeaMoss said:

That's cuz these elementary arithmetic questions are so boring ... at 60 miles an hour, how long does it take Freddie to drive to Lisa's house, which is eleven miles away ?

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He didn't go, .she dumped him 3 weeks back.

NAST555 said:

20 min, because he stopped off to buy her a bunch of flowers on the way. maybe more because he realised that the flower shop doesn't accept cards so he had to go withdraw cash first.

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Limy Sami said:

He didn't go, .she dumped him 3 weeks back.

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You got it wrong, Freddie had to get $200 cash and some flowers cos Lisa's a callgirl. I remember when she used to charge $100 and you didn't have to take flowers.