quote: Have you ever seen a part with NEGATIVE draft that somebody INSISTS can be molded? Seen that too, several times. Especially a closed, interior contour with a one degree negative draft. Actually you can do an injection mold of such a feature - ONCE. Then you throw the mold away with the molded part in it. I saw that done once because the project manager insisted that his "pet" engineer couldn't be wrong.

The 2D chamfer on a a contour toolpath is a very powerful feature - you can break a flat 2D edge just enough that you need a magnifier to see it - without a lot of calculations or tool comp to get there. Multi-flute chamfer cutters work very nicely to give a clean edge-break. No offense taken, James. I have had to scrap entire designs because the engineer in charge did not take into account that it had to be put together - have you ever tried to install a blind fastener FROM INSIDE THE CLOSED BOX! Seen it designed that way. Unfortunately, a lot of engineers DO get into a mindset that won't consider the possibility that there are better ways of doing things. I have even had experienced engineers go through 3D CAD training only to promptly go back to drawing everything in 2D mode. I refuse to draw in 2D mode when I can "make" the part in virtual reality, fit the pieces together, check clearances and fits (with the tolerances applied), and be absolutely certain that the assembly will work properly BEFORE I cut metal. As I am sure that all of you know - Its REALLY tough to stick that metal back on..... arggghhhhh - It just occurred to me that I am guilty of hijacking this thread..... Sorry guys

As both a Chief Engineer for Honeywell and an owner/operator of my own job shop I fully understand the comments made here about engineers designing 90 degree inside corners and other non-produceable features. At times it is tough to know which side of the fence to come down on. I spend a lot of time teaching engineers how to properly represent the parts they really want without overspecifying them (the old 4-decimal places on a piece best cut with a hacksaw). Some of it takes and some never seem to get it. On the flip side, I have dealt with machinists who wouldn't consider changing the way of doing business even if it saved having to deburr the parts by hand. In the majority of cases it is a simple case of properly educating the individual. I do concurr that "apprenticing" mechanical engineers in the machine shop is a good idea. I have done my time in a tool & die shop along the way. About 30 years ago, I spent my first year as an engineer with Fairchild going from department to department learning every aspect of business (from the assembly line to purchasing). It was a major eye-opener. Corporations just don't do that anymore and I believe that the entire workforce suffers as a result. Having spent several years both drafting and cutting my own parts, I do NOT draw in the chamfers, edge breaks, and other such features on the control drawing. These items are handled best by notes IMHO. The additional lines tend to confuse me (and I drew them!) when I import them into MC. MC has some very nice functions to handle items like edge breaks and larger chamfers on the top edges. In MC, I do add in the vertical edge breaks in my cutting geometry, but a button to do edge breaks would be nice. Just my .02

BTW I am using MC 9.0SP1, a modified MPFADAL post, and a Fadal 3016L. Thanks again. I just KNEW that the blasted answer was staring me in the face - I just could not see it!

Keith, It just slapped me in the face!!!!! I was using a 0.0498 (10%) lead-in line and arc. TOOOO BIGG for a 0.650 hole with a 0.500 cutter. The lead-in, lead-out was too big and it didn't actually USE the lead-in, lead-out - it was plunging. Therefore NO compensation. Duh..... Changing the lead-in, lead-out as you suggested did the trick. The really sad part is that I KNOW this...... Must have had a senior moment. Thanks all.

This one has had me pulling hair for several hours. I suspect that the answer has been staring me in the face, but I just can't see it. I am pre-drilling a 1/2-inch diameter hole 0.7-inches deep then using a 0.500 diameter M.A. Ford endmill to finish the inside diameter to 0.625 inches (using contour). I have a small lead-in, lead-out selected (about 0.05 inches)and wear comp selected for the tool. I get a G41 and the D* in the posted code for the endmill, but regardless of the amount of offset I put in the offset table for the tool in the machine - no changes in the cut diameter..... Using a Fadal 3016L. The tool comp seems to work just fine when I use it in other paths - but the lead-in, lead-out is larger. Does this mean that my lead-in, lead-out is just too small??

Thanks everyone, looks like some good places to start - particularly with the HSS tooling. I didn't think about it, but most carbide has a blunter cutting angle than the HSS. It makes sense that it would shear the plactic better. I am using a semi-synthetic coolant and tend to stay around 6800 rpm as a max (7500 max spindle - but it heats up fast above 7000 rpm). Lucky7: The material is a solid, high-density polypropylene rather than the expanded bead stuff. I am unsure of the additives to make it black. It about the density of Delrin. It also sounds like a short peck with a fast feed might be one ticket. Thanks again. When I get the stock in (next week - I only had a small piece to muck about with right now) I will let you know what the ticket turned out to be.

Does anyone have any experience in milling black polypropylene. I am looking for suggestions on speeds, feeds, and tooling choices. Machinerys' Handbook wasn't much help..... The various plastics options in job setup don't appear to be working very well. Thanks.

I had exactly this problem with my Fadal 3016L. The problem was the unnumbered date line.......sending all unnumbered or all numbered works. Sending a mix of unnumbered and numbered, particularly in the header section, would lock my 3016L every time. The code you show is otherwise what I run. In the psof section of your post it should read: "%", e n, *progno, "(", sprogname, ")", e n, "(", "DATE=DD-MM-YY - ", date, " TIME=HH:MM - ", time, ")", e pbld, n, *smetric, e The "n, " in front of the date line is what is necessary to add a line number in the posted code. The "M3E1" should be fine for a Fadal 4020 with the control in Format 2 mode. Format 2 mode should be the default.

God Bless! This is a wonderful Christmas present. Enjoy...

I have a Stevens plate for my mill. I really like it for quick fixturing on the short-run parts I generally run, but chips DO like to pack in the screw slots! Since I mostly run aluminum and brass, I have acquired some of the plastic magnet sign material to cover most of the plate when machining - keeps the chips out of the screw slots. You can't use the magnet stuff if you are machining steel or iron though - the chips just hang around and won't flush off. Just be prepared for a slight case of sticker-shock! [ 12-07-2002, 12:16 AM: Message edited by: MetalMarvels ]

Hmmmmm - very rusty, but.... "There are many people in this forum who speak French. You are in luck." I think that was a loose translation.................

OMG - that must really make me a loser. I am sitting in the garage, running parts, programming the next one, and perusing the forum!

Done and Done.

Got it James - it just doesn't work the way it used to..... I suppose it is true - nothing remains the same.

You absolutely need something for coolant/chip flush (air blast/mist or full flood) because the chips will build on the tool edges in a heart-beat and will turn your tool into an aluminum lollipop. I prefer using a radius-tip tool, as stubby as I can get away, with for ripping stock off in a hurry (DuraMill or MA Ford) before switching to the ball tool to finish. I also typically run the gain up on the servos on the finish pass.

Amen! We do indeed owe a debt of gratitude to all of our past and present men and women in uniform. I will never forget how badly my Dad was greeted when he stepped off the airplane from Vietnam. He was told not to wear his AF uniform back to the States! He flew A1-E's from DaNang and Pleiku from 67-68 and was shot down twice while trolling for AA batteries. Three of his best friends didn't come home and one has never been found. My brother-in-law is a retired Navy Chief who served in our "brown-water" navy in Vietnam and my sister is a Navy Captain currently at Norfolk. I am proud of them all. God Bless our Armed Services!

In MC 9.0SP Mill Level 3, "Define Tool" tab, "Parameters" tab - why does changing the "% of matl. cutting speed" or "% of matl. feed per tooth" no longer affect the feed rate when the "Calc. Speed/Feed" button is pushed again??? Changing the Feed Calculation from "Material" to "From tool" in the "Job Setup" page doesn't seem to have an effect. It worked in MC8. [ 11-11-2002, 03:11 PM: Message edited by: MetalMarvels ]

Yeeehhaaaa, I can go home happy now. I have learned at least one new thing! Thanks also for the tip, James. Love this forum.

Whew.... At least this way you will still like yourself in the morning!

The last place that I worked needed a custom, CAT-40 holder. After 2 weeks worth of work, they got what they thought was a good product, put it into the mill and stuck it........ The spindle had to be removed and disassembled to remove the holder. It turned out that the taper on the holder was off by less than 0.1 degrees. A custom-ground holder from a group that makes holders for a living cost only $560. The in-house holder cost in excess of $5200 (the spindle nose was trashed! plus all the labor and tool time). DON'T DO IT!!!!!!!!!!!!!!!!!!!

I really love using my wheel mouse for zoom functions in other programs. I also have been wondering why MC didn't have such a useful feature. Looks very good.

If I have properly understood your question... The process from the main menu is: File - Converters - Autodesk - Read File - Select Files of Type (*.dwg, *.dxf, *.ipt, *.iam) - then select the drawing filename and open it. Works well with Autocad 13.0 - 2000 and Mechanical Desktop 4.0 and 5.0 drawing files.

quote: He spots a 2L bottle of Mountain Dew and decides to take a drink of it. He says to himself "This tastes like pi**". He asks the mechanic, what is this? And he replies "it's my urine!". So someone really HAS bottled instant "yellow snow". ROFLMAO

I have also been using the CIMCO editor and have been very happy with the utility to date.