IS this question too hard?

[Harryman]

Hmmm... Experience, or crunch the numbers, I wonder if anyone out there can do both? C'mon guys, blow the dust off the binomials and send in yer answers.

 

Harryman practicing spelling D'OH in case I got it wrong.

[Bullines]

Funny anecdote I once read in a comp sci text regarding experience and precedence (I'm paraphrasing this):

 

Jill was preparing to make a prime rib for a family Sunday dinner with the help of her young daughter Mary. Jill proceeds to cut one 1" off of one end of the prime rib and places it in the roasting pan. "Mommy", Mary asked, "why do you cut some off of one end?". Jill replied, "that's the way your grandmother showed me how to make prime rib". When Jill's mother, Margaret, arrived later that afternoon for the dinner, Jill asked her mother "Mom, why do we cut an inch off of one end of prime rib?". Margaret replied "That's the way my mother did it. It must have something to do with making the meat juicier or something". One day, Jill was going through a shoe box filled with odds and ends that her grandmother (Margaret's mother) left her before she passed away. Jill noticed a small notebook called 'Recipes' and flipped to a page entitled 'World-Class Prime Rib'. The instructions began:

 

1. Heat oven to 450 degrees.

2. Cut off 1" from one end of the prime rib and put it in the roasting pan.

 

Beside step 2, a note was scribbled in the margin that read: "we need to buy a bigger roasting pan when we can afford it".

 

I thought it was funny I'm not bashing experience; since both experience and problem solving are valuable in this world. I'm just sticking up for the, ahem, "college boys"

[Scott Bond]

quote:

---

May I ask when in the world anyone in this trade would need to answer that question?

---

In my shop that would be right before that engineer gets wacked .

 

Scott teh' I think the Chineese asked that question, so they will have enough time to finish our work.

[chris m]

I AM an, ahem, college boy and I am not a fan of questions designed to "make people think". I much prefer questions that one would actually need to confront in the practice of the profession.

 

If you need to know which train would arrive in Minneapolis first, ask somebody else.

 

C

[jbel]

Bullines,

 

quote:

---

I'm just sticking up for the, ahem, "college boys"

---

Hey.. no hard feelings!!

 

jbel

 

journeyman tool and die maker

mastercam programmer

3rd year ME student

[Harryman]

Here's a real world math problem.

 

The new G128 macro I got from Mazak reads the Z wear value from the Tool Data Page. Problem is, after a reset, the tool will go too deep by the wear offset amount, and when the wear value is adjusted via auto tooleye routine and program run continues the next feature will be too shallow by the wear offset amount!!! I just confirmed this by programming an adjustable length tool to press on a travel indicator.

 

I can get college credit for sitting in a classroom answering BS like our academic question of the day, but not for something as practical as what I'm currently eyeball deep in. If I solve the practical question, the boss says, Hmmm, How tough could that have been to solve? A blue collar figured it out. If I solve enough of the BS questions, I got a shot at being called Engine EAR.

 

Hey Larry, do you teacher types ever consider real world stuff for college credit?

[jbel]

Harry,

 

Maybe good Engine EAR's do solve real world problems and this one just happens to be BS???

[jbel]

Good being the operative phrase.

[Harryman]

My point is, one becomes an Engine EAR by solving BS.

 

Solving practical problems gets one JS.

[the1yyz]

pi*D*N

CS = -------- (unit: FPM in inch units)

12

 

pi*D*N

CS = -------- (unit:MPM in metric units)

1000

 

where CS = surface cutting speed

D = diameter of rotating part or tool

N = RPM of tool or workpiece

 

--------------------------------------------

12*CS

N= ------ (Inch unit)

pi*D

 

1000*CS

N= ------- (Metric unit)

pi*D

 

The surface cutting speed at which material is a given quatity and is normally obtained from a machining data handbook or by experience. Tooling sales personnel can also make recomendation and to these settings based on extensive trial and mutliple error.

 

 

[CAM-mando]

L Hanft,

 

You should consider also a remedial course in cutting speeds. 360SFM for HSS in Steel

[Allan Brown]

At In-House we hire a mixed bag of skilled trades people and college/university grads. A few have both backgrounds under their belts. Everyone owns up to what they don't know, and we partner together to get things done without attitude. Everyone learns along the way.

 

I contribute much of our technical success to this approach, which seems so basically essential for our industry, yet still proves to be unique.

[Harryman]

You sound like a good boss Dave.

[ScottyB]

My job title says "Engineer"

But in reality, I just make the program, put on a cup and push Cycle Start.

Thank you, Fanuc, for making the controller just big enough to get my UPPER body behind.

Oh yeah, I dry run the programs I am less sure of. It doesn't hurt when I get hit in the cup by air.

 

"Learning from experience is good, learning from someone else's experience is Better."

[jbel]

Dave,

Can I come and work for you?

[Müřlıń®]

Actually CAMando...you can take an extremely large cut with HSS.

 

Remember FEED cuts....Speed doesn't......

 

I have taken off 3/8" per side on some stuff in the past on my old engine lathe with HSS.

 

But Slow speed is the key.

 

 

Murlin

[chris m]

quote:

---

Remember FEED cuts....Speed doesn't......

---

 

IPR X RPM = IPM

 

1200SFM x 2" DIA x .009 IPR =20.6 IPM [ceramic]

 

600SFM x 2" DIA x .016 IPR = 18.3 IPM [carbide]

 

Speed doesn't cut?

 

C

 

[ 10-23-2003, 04:04 PM: Message edited by: chris m ]

[L Hanft]

This was the final question of a 50 point bonus exam.... for those students that need a few extra points and were willing to take the challenge. The regular exam contained questions that many may feel are more realistic and practical in real life. This question was meant to challenge and provoke thought.....

 

Harry, what color of sheeps skin do you want.... nice job!

[crazy^millman]

Well sir I think you need to understand that to invoke thought is great but have you taught your people the priciples of machining to the point that they could answer this question.

 

The formulas for do these calucations do require a little more thought on your part. I take an rocket and lauch it from here to the moon at that distance is 360,000 miles (which it is not) and the rocket travels at 5000 mile an hour how long does that rocket take to get to the moon. The answer in your vacuum would be 72 hours. Oh but then the real world comes back into play here we have all the real world variables that come into play that make this answer wrong outside of the vacuum of your question as metioned by others here in their own ways.

 

Horsepower is the unit in which power that has been adopted for engineering work. One horsepower is equal to 33,000 foot pounds per minute or 550 foot-pounds per second. In your example given you have not give us the Varaiable that tools are sharp as required for the correct calcuation. It has also been given to us that the horsepower spefic to the Material is .60 hp/cu in/min which in realty is the Kp vaule of experimentally used to determine the power required to cut this material usign an assumation that the power will be held constant giving us a constant horsepower.

 

The value of the power constant is essentially unaffected by the cutting speed, the depth of cut, and by cutting tool material. There are however factoers that do affect the vaule of the power constant and therby the power required to cut the material. These factors include the hardness and microstructure of the work material, the feed rate, the rake angle of the cutting tool, and the condition of the cutting edge of the tool, whether it is sharp or dull. All metal cutting tools wear as they are used and are expected to continue to cut as the cutting edge become worn. A worn cutting edge requires more horsepower to cut than a sharp cutting edge. Again something not accounted for in your vacuum Word question.

 

We then come to the last part of the missing information of this equation. The machine tool transmits the power from the drive motor to the work piece, where it is used to cut the material. How efficiently this is done is measured by the machine tool efficiency Factor in this Case E.

 

We are all very capable of doing this equation and can give you answers to your Vacuum but this is not real world equation you are aking us to solve here.

 

Crazy Millman

 

All information taken from Machinery's Handbook 24th edition for reference

 

[ 10-26-2003, 01:40 AM: Message edited by: Millman^Crazy ]

[Rekd™]

Lol @ Millman...

 

Are we a tad bit bored today?

 

'Rekd

[Toolfab]

Bravo Millman...lol ::my head hurts from reading that::

[Fig sign]

Millman !

 

Taht was great !

 

 

Now listening : Deep Purple "Highway star '

[L Hanft]

Sorry I offended so many.... this wasn't about anything but solving a puzzle...... Thought it could be fun.... was the puzzle impracticle, yep... but then again all the bent nail, ring and string puzzles fall into the same catagory.. me I just like solving puzzles

[Scott Bond]

Hi L Hanft, IMHO this is a great thread , I participated, even if by just stating early that,,I could not answer the question.

Today Dave posted this:::::

quote:

---

At In-House we hire a mixed bag of skilled trades people and college/university grads. A few have both backgrounds under their belts. Everyone owns up to what they don't know, and we partner together to get things done without attitude. Everyone learns along the way.

 

I contribute much of our technical success to this approach, which seems so basically essential for our industry, yet still proves to be unique.

---

I am in the middle of that mixed bag skill sets somewhere, not that I work for Dave but I do have the same trade. I agree, and identify with the above statement from Dave.

It is amazing to me how often it takes everybody to make a team. It doesn't matter just exactly what each person's skill sets are,,everybody has the same worth as a person.

Scott teh' I make this stuff everyday, and everyday I make stuff I make it the best that I can.

 

[ 10-23-2003, 06:09 PM: Message edited by: Scott Bond ]

[Harryman]

I certainly don't think anyone was offended here. What good is a debate without a little heat. Or a great thread without a rant or two.

 

Nothing beats a bright green diploma. Like this happy character.