I was wondering if someone could kindly educate me as to why the stylus faceting is meant to point towards the user, instead of the other way around. My natural inclination is to think of the faceting like the bow of a ship, and faced it towards the oncoming plastic. Eg, turned around 180 degrees.
Is there a geometric advantage to having the flat side instead of the bow towards the rotation?
Thanks!
Stylus orientation question
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Re: Stylus orientation question
Hi,
If you turn it the other way, there is no cutting edge. Like the bow of a ship, it will plow through the lacquer and displace it, but not cut. In fact, running the stylus that way is a hack that is used to turn the cutting stylus into an embossing tool. You want to present a single line cutting edge. The back angle of the two facets serve to keep the stylus from hitting and rubbing the side walls of the just cut groove as the stylus moves from side to side. This angle sets limits on how fast and far you can move before the facets hit the groove walls. Think of it as a form of slew rate limiting. If you have any experience with a metal lathe, the cutting tool geometry is much the same (see relief angle), but optimized for the task at hand. Also note that modern styli can have very tiny burnishing facets added that, in effect, dull the cutting edge. Used along with some heating, they lower the noise floor. The downside is a slight reduction in high frequency response. Hope that clears things up for you.
Mark
If you turn it the other way, there is no cutting edge. Like the bow of a ship, it will plow through the lacquer and displace it, but not cut. In fact, running the stylus that way is a hack that is used to turn the cutting stylus into an embossing tool. You want to present a single line cutting edge. The back angle of the two facets serve to keep the stylus from hitting and rubbing the side walls of the just cut groove as the stylus moves from side to side. This angle sets limits on how fast and far you can move before the facets hit the groove walls. Think of it as a form of slew rate limiting. If you have any experience with a metal lathe, the cutting tool geometry is much the same (see relief angle), but optimized for the task at hand. Also note that modern styli can have very tiny burnishing facets added that, in effect, dull the cutting edge. Used along with some heating, they lower the noise floor. The downside is a slight reduction in high frequency response. Hope that clears things up for you.
Mark
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SONARC
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Re: Stylus orientation question
Hi there - I think this actually relates to a conversation I was just having yesterday with Mike, oddly enough.
Just to be sure I'm reading this correctly and understanding it, the two facets you refer to would be on the left side of this image?
Just to be sure I'm reading this correctly and understanding it, the two facets you refer to would be on the left side of this image?
markrob wrote: ↑Fri Jul 16, 2021 4:02 pm< - snip - >The back angle of the two facets serve to keep the stylus from hitting and rubbing the side walls of the just cut groove as the stylus moves from side to side. This angle sets limits on how fast and far you can move before the facets hit the groove walls. < - snip - >
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karl hungus
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Re: Stylus orientation question
Hi Markrob
Thanks for taking the time to explain. That makes sense now. I forgot about the embossing option, although I hear in stereo its not as effective to emboss.
So have you found that you need to angle it slightly toward the rotation like some suggest, or is straight down ok?
Thanks for taking the time to explain. That makes sense now. I forgot about the embossing option, although I hear in stereo its not as effective to emboss.
So have you found that you need to angle it slightly toward the rotation like some suggest, or is straight down ok?
Re: Stylus orientation question
The facet(s) in question are just to the left of the front face in your photo. You can't see the burnishing facets (if present) without a microscope.
I have moved to Mike's conical style embossing styli. The new design from Epos looks really interesting. I've been playing with duplicating his work. As far as stereo goes, its amazing to me that its present at all. I do mono for my embossing. I'm fine with that. I do tilt my head back slightly maybe a degree or two. I've been shooting for a groove width of about 1.5mils. For me, that happens at about 20-25g.
I have moved to Mike's conical style embossing styli. The new design from Epos looks really interesting. I've been playing with duplicating his work. As far as stereo goes, its amazing to me that its present at all. I do mono for my embossing. I'm fine with that. I do tilt my head back slightly maybe a degree or two. I've been shooting for a groove width of about 1.5mils. For me, that happens at about 20-25g.