VF4 ss help please

Hello, just joined so intro first...
Ross, 21 from uk, injection mold maker turned F1/motorsport composite mold maker. used fair few machines for the amount of time i've been in engineering..fanuc T14ibl, hermle c600, haas vm2, haas vf4ss, haas vf2 tr, couple ancient leadwells, hurcos, two cincinnati sabre 1000's, bloody hundreds of bridgeport interacts, doosans, yangs, colchester tornado and all the other associated machines toolmakers use. wirers, sparkers, grinders etc.

anyway, the vm2 and vf2 tr that i used to use both had all the high speed options fitted from new. the vf4ss i've just started using doesn't appear to have any as it stutters whilst cutting at feed rates above 8000mm/m on 3d surfaces. which of the options will cure this? i used the 15 line look ahead and that calmed it down a bit but its still a bit crappy to be honest. its running through rs232 and the other 2 haas's were on ethernet...is that part of it? i figured it will be able to run a program more smoothly if it has the whole program in to start with?? apologies if its a silly question and thanks in advance for any help

What's the error delta on your program, .00005"? If you have a 3D program with lots of operations per inch, it's going to take a lot of bandwidth to keep up. At 115200, which I doubt it is, you're talking like 200-300 lines per second of G code. AFAIK, you need something like 100 lines of lookahead to keep up with accelerations.

If it's a VF2SS, it's already got "high speed machining", the SS isn't available without that, AFAIK. Either pony up for the memory upgrade, stuff a compact flash PCMCIA card in it, or cut your programs up to run in the memory you have. DNC over serial was never meant for high speed machining.

You can get 115kbps from a betatronics I232 system on a haas.

http://www.beta-a2.com/i232.html

A whole lot cheaper than more memory, or eithernet. And I don't think you can stick flash mem in a haas.

It might also be worthwhile to verify with the programmer that the surface tolerance used in generating the toolpaths is reasonably in line with the actual part requirements. If a surface needs +/- .005, and the programmer tolerances the toolpaths to .0001 "just for good measure", the bulk of the code to be executed per unit time expands by a few orders of magnitude.

OTOH, there have been numerous complaints of stuttering directed specifically at the SS model Haas mills on various machining forums. Enough so that it would seem it takes more than just a substitution of screws with 2.5 times the lead to create true high speed machining capabilities.

it a 4 ss, not 2. i suggested to them to try mem upgrade. the high speed option is listed as an option on the vf4ss so i dont think it has it but as far as i know it only reads 80 lines ahead anyway. i honestly think it is more to do with the ball screws. the vm used to run massive 3d engraving programs at 480ipm using tiny 0.001 inch step downs and ran fine. i find it odd that the much slower vm will run programs faster than an ss. i'll get them to do the memory, get high speed option fitted and, if they can, fit ethernet and hard drive. i'll report back if that doesn't fix it - then it must be the ballscrews. already had problems with it digging and leaving dimples that the vm didnt on the same programs. the tolerances are +- 0.0001mm on the drawings but 0.001mm realistically, all safety critical F1 components.

If there is a T next to the high speed machining option in the machine it has a 200 hr trial period. Might be worth looking at.

we've bought the high speed option, paid today, get code tomorrow...1500 pounds for a code. bit cheeky.

high speed option fixed the stuttering around corners, also makes it do dog leg rapids. ah well. cannot believe they sell ss's without high speed as standard. we wont buy another haas because of the trouble we've had with this, not my choice, management