Make Inscribed Circle parameter available for metric inserts as well

Verifun · 2015-07-01 23:12:59

IÂ´d love to understand the rationale for the insert definition do not support IC (Inscribed Circle) when metric tools are created.

Most of inserts are the same worldwide (ISO) and yet CGTech defined that the IC is based on the edge length and not the other way around in the metric system. Nose radius of inserts are predominantly delivered in metric dimensions.

The result is a HUGE difference in the size of metric inserts because the edge length itÂ´s not reliable nor effectively measurable depending on the insert. We set the approximate value and the result is a lot of play between the insert and the tool holder. Quite often if you enter the "L" value from the vendor catalogue in ToolMan, the result is a shrunk version of the real insert.

Whoever decided for this approach didnÂ´t considered much how inserts are selected in real life.

Last edited by Verifun (2015-07-01 23:16:37)

Verifun · 2015-07-08 01:38:36

Below some studies and further explanation about what IÂ´m talking about:

Example: Insert parametric type "V" (35 degrees)

VERICUT supports the ISO standard - It supports the definition of letters and their associated shapes. However, it does not support it correctly due to the lack of support to the IC (Inscribed Circle) value for metric inserts. This is a global value - All ISO inserts are built based on IC, regardless the unit system.

Insert in inches: (Dimension D is equivalent to the IC):

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Insert in millimetres:

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In metric inserts, the IC value is a resultant from the value of "L". This is wrong.

In real life inserts, all "L" values informed by the insert manufacturer are always approximate values, with the exception of "S" (Squares) inserts. With "S" inserts, since all sides are perpendicular to each other and tangent to the IC, "L" is equal to "IC".

In order to be created with the correct dimensions in the metric system, the insert needs to be created by the same method of the imperial system. If CGTech wants to support the "L" value, then they should offer "L" for the two systems, or allow the user to use "D" for both systems, or choose the dimension type that will set the size. If you choose "D", then "L" is the resultant dimension, and vice-versa.

I think the last is the best way to enhance it since all metric users so far have built their inserts using the innacurate way ("L"), and VERICUT needs to support this as well. A checkbox to select the driving dimension ("D" or "L") and convert the value to the equivalent would be a decent solution.

VERICUT currently uses double standards, and this is WRONG.

Example: Insert form "V"

Dimensions of a VNMG insert size 16 (16 is a reference to the approximate size of the theoretical edge length, which is in fact 16,606 mm - A difference of 0,606 mm (Huge).

Notice that this difference will exist in every edge. In the insert perimeter, using the 16mm "V" insert as an example, the total difference is more than 2.4 mm. It's a big difference.

Please refer the dimensions of an ISO catalog. Notice that the "L" dimension in the catalog is 16 mm - However it is just a reference to pass an idea of the holder size and edge length. In reality, the IC dimension defines the size, and with an IC of 9,525 mm (3/8"), the real length of the edge is 16,606 mm, not 16mm.

In order to came to the conclusion that the real edge length is 16,606mm with an IC of 3/8" (9.525mm), I had to draw it in ACAD, because it is impossible to mentally come up with the correct "L" value, once that the length "L" is in function of the tangency of the angles and the IC, and the shape changes for each type of insert. ( "C" , "D" , "K" , "L" , "T", etc)

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Below, drawn over each other, are the two inserts with the same dimensions, one defined in metric and the other in inches. The inches insert has its contour drawn in cyan, and the metric one it is drawn in magenta.

Notice the huge differences in size, notice the length between the tips (27,995 - 26,798 ) - A difference of almost a 1.2mm.

Please notice below the IC of 9,525 mm (Cyan contour), which generates a theoretical length of 16.606 mm - (See in the tool manager screenshot above that in the definition of the metric insert, the "L" dimension is measured to a theoretical point)

Notice that the contour in magenta, which is the metric insert, that an edge of 16mm (Which is the approximate measure of edge, informed in the insert box) results in reality in a IC of 9,177 mm, not 9,525 mm.

This huge difference between inserts (And it happens with all inserts with the exception of the type "S") results in a large gap between the insert and the 3d holder, as shown below, because the metric insert is smaller than the imperial insert, as the study below shows.

VERICUT is all about the GIGO philosophy (Garbage In / Garbage Out), and itÂ´s just plain wrong to have a very basic thing like an insert size to be wrongly defined due to the lack of a basic common feature that is the support of the IC value for a metric ISO insert.

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Last edited by Verifun (2015-07-08 10:23:56)

Verifun · 2015-07-13 16:58:23

SCR #14892

Verifun · 2015-07-15 20:16:46

Just to give you guys an idea, look at how complex CGTech made to us to define a metric thread insert, which involves lots of geometry.

Dimensions that ALL tool vendors provide:

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How users in the imperial system feed ToolMan for a thread insert:

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How metrical users have to deal with it:

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I really appreciate the quality and power of VERICUT software, but the rationale about the way CGTech implemented support to metric inserts does not make sense. ITÂ´s a half baked implementation IMHO.

Verifun · 2016-08-11 02:16:40

I refuse to forget how bad CGTech handled this...

VERICUT Users' Forum

#1 2015-07-01 23:12:59

Make Inscribed Circle parameter available for metric inserts as well

#2 2015-07-08 01:38:36

Re: Make Inscribed Circle parameter available for metric inserts as well

#3 2015-07-13 16:58:23

Re: Make Inscribed Circle parameter available for metric inserts as well

#4 2015-07-15 20:16:46

Re: Make Inscribed Circle parameter available for metric inserts as well

#5 2016-08-11 02:16:40

Re: Make Inscribed Circle parameter available for metric inserts as well

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