Freesteel Blog » WorkNC, art, and Mori Seiki

WorkNC, art, and Mori Seiki

Wednesday, January 16th, 2008 at 12:10 pm Written by:

This press release about the winner of Mori Seiki’s Cutting Dream Contest (news inexplicably released from “Gloucestershire, UK”) cites WorkNC as the CAM system of choice by Kawanami Ironworks of Kyoto for cutting their amazing metal jacket.

So much for my recent rant about what appeared to be the effects of WorkNC system in Berlin.

The engineer responsible at Kawanami Ironworks explained the process. “The model was entirely made up of free form surfaces, so the most difficult task was planning the sequence of operations and positioning the job datum.” The ultimate aim was to produce a finished product which properly represented the look and feel of the jacket. He continued, “The majority of the part was cut with WorkNC’s machining between two curves strategy. We found that this gave the best result for expressing the softness of the fabric.” Kawanami Ironworks’ engineers also used many of the other finishing toolpaths in WorkNC, these enabled them to pick out the fine detail and access confined areas without tool or holder collisions.

I stand in awe. However, this is clearly in the 5-axis department. I am a 3-axis expert, although getting a bit tired of it now. Eventually I will get all the programming I need done and then I can move on. 3-axis is special because there is no more than one cutter location for every point on the model. This means the field isn’t endless because the basic algorithms and geometric structures on which everything else is built can be counted on the fingers of one hand (even if the most fundamental one is generally overlooked by academic study). 5-axis has two degrees of freedom for every point on the part. This makes the whole business a lot less obvious.

What’s missing is a good video on youtube of the winning entry. WorkNC, at least, has some videos of small operations on their webpage. (Not all of them impressive, but it’s moving in the right direction — video is the natural media for promoting these products.)

Meanwhile, the sponsor of the competition, Mori Seiki machine tool company (Japan), looks highly interesting — not only because they have an eco policy.

Their Digital Technology Lab (DTL) in California has…[link]:

pioneered in proactively working with the following CAM software vendors in helping them develop post processors for Mori Seiki machines. Through this collaboration our mutual customers will now be able to get reliable post processors as soon as they purchase Mori Seiki machines, hence jump starting their productivity. Working with several top CAM software vendors enables our customers to choose the CAM software(s) of their choice and be able to fully utilize the machines. DTL provides post processor specifications, requirements, testing and consulting support to the CAM software vendors. DTL also provides assistance in creating realistic machine solid models to our partners, so they can build Machine Simulation solutions as an added benefit for our customers.

About time too, I’d say.

The history of post-processors, in my opinion, encapsulates everything that is wrong in the CAM industry. There is virtually zero communication between the machine tool manufacturers and the CAM software developers. The language accepted by the machine tools has never been successfully standardized, and continually forks. And the machine tool manufacturers do not take any responsibility for the chaos they have created.

Contrast this with printer manufacturers who will distribute printer drivers for their printers and your operating system without any questions. There are thousands of them. I’ve never known why they can’t all use the same driver since they all do the same thing with the same input, so why not put the transformation which specializes it to the hardware in the printer itself?

With machine tools, the CAM system supplier has to build the post processor to drive the machine. You can phone up the manufacturer, but the most you will get is a copy of the manual documenting thousands of features you never need to use. No working code. Nothing.

So usually in the CAM company someone who doesn’t know anything (for example: me) botches something up to replicate the look of a file which the customer has supplied until he is happy with it. Maybe it sets the feedrate on every single line, or just when it changes. Maybe feedrates are on their own line, and rapid motions are programmed with G0, F9999 or FMAX, you never really know why. But as long as the customer is eventually happy, you never know if he’s losing 15% of the efficiency of the machine because there are too many unnecessary characters and causing block starvation. Amazingly, we heard problems about how machine tools stalled creating marks because it moved faster than it processed the motion instructions. Given that the machine is always varying its speed to go round corners outside of the control of the instructions, why couldn’t it slow down a little to avoid this stalling? Why couldn’t we get a warning? We were in no position to debug it. Usually it needs lots of points to go round corners, so should be going slower anyway. As the speed of processors was increasing faster than the speed of the machines, we ignored this problem and hoped it would go away.

I wrote the postprocessors at NC Graphics for six months before I even saw a machine tool. Even today there’s a man who makes a living by writing post-processors from scratch. Post-processors should be the first place where open-source software gets a foot-hold in this industry. Machine tool manufacturers should write them, distribute them, and maintain them to encourage best performance from their machines.

Mori Seki has a page explaining the status of post-processor development for each CAM system, eg MasterCAM. Unfortunately these link to the CAM vendor’s webpage rather than to a direct download. They seem to be reluctant to step on the toes of the CAM software suppliers. They say:

Mori Seiki or DTL do not recommend any CAM software in particular and it is up to our customers to decide the best choice for their needs.

Why! What are they afraid of? Why don’t they do some benchmarking and give us guidance so that we know which parts of our software are substandard, and which parts are great? Nobody has any idea.

1 Comment

  • 1. Tyler replies at 28th March 2008, 11:24 pm :

    Couldn’t agree more about your points on post-processors

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