# PCB Heaven

## General Category => Maths, Geometry, Physics and others => Topic started by: sysKo on May 27, 2009, 18:01:16 PM

Title: Calculation for the arc using the height of the arc
Post by: sysKo on May 27, 2009, 18:01:16 PM
I do not know where to put this question, hear or in the CNC? Anyway.

I (re)ask again for this. I have a part of the arc. I want to calculate the radio of the arc. The height of the arc i know it. How to calculate it?

K.
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on May 27, 2009, 20:13:05 PM
It's a good board the one you chose to post your question.

So... I think you are missing of something. The given data are not enough. We need either the angle of the arc, or the chord of the arc... Please specify.

My regards ;)
Title: Re: Calculation for the arc using the height of the arc
Post by: sysKo on May 28, 2009, 18:19:48 PM
Chord is the open? You know... The open of the door
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on May 28, 2009, 20:19:20 PM
I suppose you want to calculate the radius of the arc, by knowing the arch chord (AKA door width - left space - right space) and by knowing the ark height.

For the people here to understand, because our conversation looks like an encoded signal, i have attached a file...

So, first to calculate the Semi_Chord. That would be the Chord divided by two:

SC = C/2

Then, the radius can be easily calculated using the following formula:

R = H2 + SC2 / 2H

I asked you to write it down not to forget. But now you can find it here whenever you want :P

Title: Re: Calculation for the arc using the height of the arc
Post by: sysKo on May 29, 2009, 18:25:57 PM
Thanks you Georg. Is this that i am look!!!!!   :o 8) ;D :D ;) :) :-*
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on May 29, 2009, 22:20:39 PM
Thanks you Georg. Is this that i am look!!!!!   :o 8) ;D :D ;) :) :-*

yes is this :D

I know ;)
Title: Re: Calculation for the arc using the height of the arc
Post by: sysKo on June 05, 2009, 22:49:29 PM
And for the draw with 3 circles? The "perispomenh"? I am sorry i do not know the english name.

Title: Re: Calculation for the arc using the height of the arc
Post by: kam on June 06, 2009, 00:00:46 AM
Perpendicular is the name. I told you you should write them down  ;)

Rtotal = H2+SC2 / 2*H
Rin = Rtotal * L
Rout = Rtotal-Rin...
Title: Re: Calculation for the arc using the height of the arc
Post by: sysKo on June 09, 2009, 16:52:18 PM
And i understand you think by this?  ??? ??? ??? ??? ??? ???
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on June 10, 2009, 23:25:06 PM
You should!

Anyway.

Consider as it was a single arc (like the first drawing attached).

The radius (that i call Rtotal) should be

Rtotal = H2+SC2 / 2*H

But now you have a parameter L, that is a number from 0 to 1. Use 0.5. You'll get what this is when time comes.

So, the internal arc will have a radius of:

Rin = Rtotal * L

and the external 2 arcs will have rad:

Rext = Rtotal - Rin

Is that clear now?
Title: Re: Calculation for the arc using the height of the arc
Post by: sysKo on June 22, 2009, 08:34:55 AM
I still make china symbols with it  :( :( :( :( :( :( :( :(

Am i stupid?
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on June 22, 2009, 16:38:17 PM
In the name of holy mary madonna

See attached image:

The Semi-cord SC is half the width (left to right) of the drawing.
The Height H is user defined
The proportion L (LOGOS in Greek is also user defined, at about 0.5 or so...)

ROL=(H2 + SC2)/2H
Rin = ROL*L
Rex = ROL-Rin

Ok So far?

Now:

X2 = X1 + H * L
X3 = X1 + L

Y2 = Y1 + SC * L
Title: Re: Calculation for the arc using the height of the arc
Post by: spic0m on June 22, 2009, 19:14:15 PM
That's the problem with CNC, they go along with maths, otherwise is just a big router.:)
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on June 22, 2009, 22:07:14 PM
That's the problem with CNC, they go along with maths, otherwise is just a big router.:)

That's the problem with operators.... not cnc... You need maths also with the hand routers. If you want to be a good operator, you need maths. Kostas (sysKo) is a "wanna be" good operator, but because of his believes that he needs no maths, he will never be above average.
Title: Re: Calculation for the arc using the height of the arc
Post by: spic0m on June 23, 2009, 10:27:00 AM
Correct, i mean just something to cut straight lines. :)
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on June 23, 2009, 20:06:34 PM
Correct, i mean just something to cut straight lines. :)

a band saw or something
Title: Re: Calculation for the arc using the height of the arc
Post by: spic0m on June 23, 2009, 22:40:37 PM
Yeah, something like that. Having a spaceship and using it as a bike. :)
Title: Re: Calculation for the arc using the height of the arc
Post by: sysKo on June 25, 2009, 22:18:49 PM
In the name of holy mary madonna

See attached image:

The Semi-cord SC is half the width (left to right) of the drawing.
The Height H is user defined
The proportion L (LOGOS in Greek is also user defined, at about 0.5 or so...)

ROL=(H2 + SC2)/2H
Rin = ROL*L
Rex = ROL-Rin

Ok So far?

Now:

X2 = X1 + H * L
X3 = X1 + L

Y2 = Y1 + SC * L

THAT IS IT!!!!!!!!!!!!! I WORK NOW!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! THANKS YOU!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
:-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-* :-*
Title: Re: Calculation for the arc using the height of the arc
Post by: sysKo on June 25, 2009, 22:19:32 PM
now yes!!!!!  ;D
Title: Re: Calculation for the arc using the height of the arc
Post by: kam on June 25, 2009, 22:56:54 PM
you are too kind and mostly welcomed