Given the end view - we are trying to develop a Z_X cross section view for a helical sweep. Then in order to design a cutting tool, we need to section normal to the helix in order to generate true shape. I have tried this in mastercam and found it to lack the required tools

What is the gear data so I can try to model something.

Kevin, You are correct, the cross section and orientation of the tool will be normal to the helix angle and inclined to the part. You will not be able to cut this type of a part using a lathe cycle for the following reasons - your pitch is in the order of 6.0" and your diameter of the part is only 3.0". In order to generate the "Thread" you will need to travel 6" in Z for every rotation of the spindle. Example - for a piece of carbide a nice threading sfm would be around 150/200sfm. This translates into G97 S191 - S254. Therefore the linear feed rate requirements for the Z-Axis will be F1146.0 - F1524.0 Inches per minute. If your machine will do this - Please let me know so I can order 3 of them... The machine dynamics for the accelleration and deceleration would also require a design of experiments to determine the lengths needed to get up to speed and to slow down without affecting the pitch geometry of the "Gear" The ways around this are to use a gear hob in a mill/turn machine application. Involute gear hobs are off the shelf items - no sense in doing someone elses work again. I am creating large diameter screw profiles and would be happy to discuss further.

KCollins - Please elaborate on the geometry a little more. If I read it correctly, you wnat to cut the gear profile on a lathe and need to know the shape of the contour?? I can see attempting a worm gear in this manner but a spur gear? The Rotation along the helix would require an infinite linear feed rate along the z-axis in order to induce enough shear for the tool to function. For a worm gear, I know pro/e uses a Helical Sweep, I need to look it up in Mastercam to see if it will create it. Otherwise - use the helix c'hook to create successive curves at required diameters, and then make a surface out of these.

Jack, I would like to refine your argument and indicate that the Stesses you are indicating will be released after the material has been unclamped. I suspect that the root question is to do with cutting material skin and relieving the residual stresses from the material condition and the effect that the plunge roughing would have on this. The answer to this is - you tell us if it distorts! The only way to know is to do it! Again Jack's point stands that if you distort the part while clamping - remember that it will release when you let off the pressure and so good luck trying to machine a quality part...

Spindle Bell Mouthing is directly related to spindle speeds and with a taper tool, would bind on stopping as the bellmouth would relax and tighten its grip on the holder. HSK (Hollow Spindle Tube) systems use this property to their advantage and also have a simultaneous fit at the face of the tool to prevent the tool from moving in the z-axis. Spindle Growth from heat on tapered roller bearings will be to blame for z-axis deviations more than the bellmouth. Coating a taper on a tool holder before insertion into a spindle is a Hack fix to a larger problem (poor/cheap spindle design). We rely on the friction between the tapers to drive the tool and to introduce something to minimize the amount of friction here is defeating the original design intent of the system. The old Mori Seiki I worked with had a knock pin that gave the retention knob a jolt to break the taper on tool change. When this malfunctioned, we did as James said and tapped the holder with a soft face mallet to break the taper. There are also on the market - "simultaneous fit" taper tooling that will engage the spindle face and allow a greater contact than the gauge line of the holder on its own. This would accomplish two things, one the contact area would handle greater cutting forces and also prevent the bellmouthing from locking to tool. Before a machine purchase - Do your homework and look around. High Performance Machining, Miles Arnone - Hanser Gardner Publishing is a must read to define requirements. With the newer technology tooling, faster cutting speeds and feeds mean more blocks per second processing and greater Inertia/Forces the machine must absorb. Remember that Accuracy/Repeatablity/Reliability are all "Published/Edited" numbers. Get testimonial information and see the machines in action at other plants.

Remember that the published insert tolerances are in the order of .005" - These inserts are pressed and sintered and even though the dies are adjusted for shrinkage, there is still going to be a normal distribution. An inserted tool will also have to have the locating points of the insert pocket absolutly pristine in order to hold the "size for size" expectation as outlined above. These points will degrade and wear with the use of the tool and over a period of time will become worn essentially making the tool body a consumable item as well. When required to have a tighter tolerance, I always use a finishing tool after using the Indexable for roughing. As sharp and free cutting as the tool may be - it is like trying to shave your beard with an Axe...

On the same topic of "Catch Phrases", I once had a calculus professor say the following to indicate something simple... "Knock em down, Row Reduce It, Readem and Weap, as easy as Mother's Milk, so simple your dog could do it!" Sometimes the eloquence is lost on the shop floor guys!

Standard Windows functionallity... In explorer Go to the c:mcam9millposts Select All right click and select delete from the drop down menu. Then call your dealer and insist that mastercam was making gcode yesterday and now it doesn't work... SP1 must have affected it somehow with a virus or something.

Glenn - Thanks, I found some of this last night and played a litte. Group - Sorry for the RTFM post...

V10 wish continued... ASCII tool libraries that can be manipulated in windows notepad or cimco edit... The encoded stuff is not nice and I have 60 similar tools to define and now I am forced to use the Mastercam interface.

V9 is your salvation for this application. Threadmilling is right in there.

Martin, Check out Louis' March picture on the Sandvik 2002 calendar. I met this guy once at a trade show, what a character - he knows his stuff... Also - Metric cutters are standard coolant thru while inch sizes are hit and miss. [ 07-03-2002, 12:10 PM: Message edited by: MfgEng ]

My wish list - as I am coding things this afternoon, Cut and Paste ability form one active file to another active file. True windows multitasking by opening multiple files concurrently. Before you get too excited James, I suggest to use a routine to lock out the cpu while toolpathing and prevent a hiccup while number crunching or only allow one file to code at a time. Most mature users will on good habit only have one file active during such a vitial step anyway.

Check the extended length program. There are absolutly no flats on them - there are also no flats on the metric shanks either. The failure I had was in a sidelock holder with only an orientation flat on the tool - not undercut to prevent pull out. -5 degree flats (whistle notches) are even more superior but try to find a manufacturer that makes them as standards... Perhaps the europeans have better physics than here in North America... I also use the Corogrip Chucks to hold the metric shanks and so a flat is not necessary.

With respect to this cutter, I am curious if everyone else notices that it doesn't like to re-cut chips. Ramping with large diameters (1-1/4) endmill style on a cylindrical shank - sucked right out of the holder and near scrapped the piece. (Poor Glenn near had a heart attack...) After machining a "Weldon" flat, things ran smooth. My favorite cutters of all time are the R200 Buttons - they run like kittens... Purrrrr.

Nick - Glad to hear you are meeting with success. We are all learning everyday.

Claus - The equation I put forth is true and your synopsis is true if you are holding variables constant. However the question posed - what should I do... Then the answer as evedenced by Bryan (someone else who knows what is talking about) is to get More Power!!

Check in the operations manager if the program number field is consistant throughout. I had distinct vales in these locations for that specific purpose. Hope this is the sol'n.

Think about what you are asking. There is no mathematical solution to express the X and A movements as an arc (your g02 is only active in orthogonal planes - g17-18-19)

With a router I would be inclined to use the higher horsepower. This will and should give higher spindle speeds. Power = torque * rpm

I could ony suggest the area funtion when in a select mode. This should highlight the inner and outer boundaries are you require.

This is one other techniques that I learned from a hatchet machinist. He claimed that he could out perfrom me picking up holes. His trick was to use a .500" dowel pin and a magic marker. Touch in X +/- and then Y +/- and average the coordinates to get to the center of the hole. He claimed this is an aerospace technique. Well he scrapped the first part and we used Allan's method from then on in.

Masternick - Thee feed rate you are seeing with the "A" motions are in degrees per minute. I have the same condition on the Integrex. Abandon all hope and think Polar...

Kevin, Use the multiple offset post from this site (MPSUBREP) and then go to the misc values page. The post will need to be modified to count the g54.1 and g55.1 and increment p as you require. I have loaded my revised file (Rotorevised.zip)and a sample of the gcode. Don't worry about the goofy graphics on the screen, as the operator is going to pick the work zero for each station.