best text size?

Hi,

Your objectives are to make silkscreen text printable and readable.

Check with your board house what minimum silkscreen width they can

reliably print.  Olimex, for example, specify 10mil (0.254mm), other

board houses give a figure of 8mil or sometimes 5mil.

You will then need to choose a text size that is comfortable to read

when assembling/debugging boards.  I go for 50mil (1.27mm) but this is

quite large.  The best way to find out what works is to print a

life-sized copy of the silkscreen layer.

To meet the silkscreen width requirement of your board house you will

need a suitable "Ratio" setting.  I use 20% which, for 50mil text, gives

10mil thickness.

You will see that most of the EAGLE standard libraries use 50mil text

and either 8% or 10% ratio, giving rather feeble 4mil and 5mil

silkscreen widths respectively.  Some board houses will struggle to

print these.  When I use standard parts, I usually "SMASH" them and

change the ratio of "tNames"-layer text to 20%*.

For non-silkscreen drawings or text (e.g. "tValues" and "tDocu" which

are generally not printed on the PCB), which are used to produce

assembly/test documentation, you have much more freedom.

In schematic symbols, 0.07 inch text (with 8% ratio) is standard.

In a thread on "eagle.userchat.eng" in November last year, Jeorge Garcia

of Cadsoft proposed a set of standards for libraries.  I'd be interested

to see if this took off.

Andrew

0xADF

• display none tOrigins bOrigins; group all; smash (>0 0); display last;

display none tNames bNames; group all; change size 50mil (>0 0); change

ratio 20; display last

On 23/06/2012 02:25, d r wrote:

I am making components for libraires, but I don't want all different font sizes as I use my custom ones and the standard ones.

 

What is the most common size so I can try to match as I make mine?

 

Hi,

Your objectives are to make silkscreen text printable and readable.

Check with your board house what minimum silkscreen width they can

reliably print.  Olimex, for example, specify 10mil (0.254mm), other

board houses give a figure of 8mil or sometimes 5mil.

You will then need to choose a text size that is comfortable to read

when assembling/debugging boards.  I go for 50mil (1.27mm) but this is

quite large.  The best way to find out what works is to print a

life-sized copy of the silkscreen layer.

To meet the silkscreen width requirement of your board house you will

need a suitable "Ratio" setting.  I use 20% which, for 50mil text, gives

10mil thickness.

You will see that most of the EAGLE standard libraries use 50mil text

and either 8% or 10% ratio, giving rather feeble 4mil and 5mil

silkscreen widths respectively.  Some board houses will struggle to

print these.  When I use standard parts, I usually "SMASH" them and

change the ratio of "tNames"-layer text to 20%*.

For non-silkscreen drawings or text (e.g. "tValues" and "tDocu" which

are generally not printed on the PCB), which are used to produce

assembly/test documentation, you have much more freedom.

In schematic symbols, 0.07 inch text (with 8% ratio) is standard.

In a thread on "eagle.userchat.eng" in November last year, Jeorge Garcia

of Cadsoft proposed a set of standards for libraries.  I'd be interested

to see if this took off.

Andrew

0xADF

• display none tOrigins bOrigins; group all; smash (>0 0); display last;

display none tNames bNames; group all; change size 50mil (>0 0); change

ratio 20; display last

On 23/06/2012 02:25, d r wrote:

I am making components for libraires, but I don't want all different font sizes as I use my custom ones and the standard ones.

 

What is the most common size so I can try to match as I make mine?

 

Thanks very much.

I'm going to use 50mil and 10% and propose that becomes the standard.