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Comment: Re:Having designed and built a 3D printer (Score 1) 203

Print heads can be tiny:
http://daid.eu/~daid/IMG_20140...

The problem is not slinging the head around. You could even do that with much more speed then is done right now.

However, the real problem is cooling and bonding. If you print quicker you need to cool the material quicker. If you cool it quicker, it doesn't bond to the rest of the material really well.

We generally speak in mm^3 / second when we talk about printing speed these days. As that's what counts in the end. Volume per time. With the accuracy we want, naturally.

- Daid, Ultimaker R&D. The Cura guy.

Comment: Move along nothing to see here. (Score 3, Insightful) 56

by daid303 (#47098719) Attached to: Servo Stock 3D Printer Brings Closed-Loop Control To Reprap

Pretty much all lies from the start.

First off, almost nobody is missing steps in their cheap 3D printers. They simply do not move fast enough for that to happen. And if they are missing steps you have a bigger issue, usually lots of friction somewhere.

Secondly, 200 steps per rotation is normal for motors. However, the drivers everyone is using do 16x microstepping, good for 3200 steps per revolution. Accurate steps per revolution. That's better then 4096 +- 2 steps.

You also lose the close coupling between the 4 axis that you need (the feed stock of the material is also an axis that you need to control), which is a big deal in running accurate prints.

The cheap hobby servos will also have mechanical play, which will cause vibrations to be transferred to the head, which will result in a reduction of print quality.

I'm also willing to argue that it's more expensive. But I didn't do the math on that part yet.

(Who am I to say so? Just a guy who has been working at Ultimaker for 2 years. Kinda know what's needed for quality 3D printing at a low price and what's not)

Comment: Re:low impact (Score 1) 50

by daid303 (#46887497) Attached to: Researchers Find Easy To Exploit Bugs In Traffic Control Systems

I worked in this area 5 year ago. The switches have been replaced by a 2nd CPU which handles safety, and cannot be overridden from the main CPU.

So, all-green cannot happen. But the systems are far from safe. System I worked on was based on Linux, had pretty much an open-telnet server running. But is intended to run on a private network, not connected to the internet. However, connecting to this network you could own all the lights in seconds.

But, as you say, the value of this would be low. You could disrupt traffic flow for a while. But that's it.

"A car is just a big purse on wheels." -- Johanna Reynolds

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