[sdiy] Fwd: Frontpanel Express line detail

[steven thomas]

Hmm ..not being able to make lines thinner than 0.4mm doesnt sound
exactly great from such a premium company. Any decent engraving
company use tapered engraving cutters and  can do lines much finer
than that (I have done so  many times myself on my own cnc engraving
machine).

Obviously FPE are not using standard v-shaped cutters and floating
'nosecone' engraving to control width of engraved characters. Probably
the engraving spindle  on their giant routers dont allow for this ..or
its too time consuming. Therefore they are likely using fixed spindles
that dont float over the metal surface like dedicated engraving
machines use.  So,  in order to avoid varying width in the engraved
lines, which can easily happen because the metal itself isnt perfectly
flat ..(even slight variations in its thickness can cause visible
variation with v shaped cutters on a fixed spindle.. which is why
floating engraving spindles were  invented ) they probably use
straight cutting tools.even in engraving.

I am also surpirsed that they quote  cutter bit +machine tolerance as
high as +0.2mm..thats rather large ..I assume the 0.2mm is from the
position error over large distances.
Most cnc machines ..even huge ones.. normally use ballscrews which are
very accurate (to microns over small linear distances).  I would  only
expect a 0.2mm error in machine position to occur only when the
spindle head traverses large linear distances on very large
panels...not in engraving relatively small text over small linear
distances!

Are you sure the quoted tool size isnt radius and not diammeter?  A
single stroke font or line with 0.2mm diammeter parallel cutter should
produce  a line very close to 0.2mm width not 0.4mm!

I have never had a panel made by FPE/Schaeffer..so I dont know if this
is a common problem.

cheers
steve

Digitana Electronics
www.synthi.co.uk

On Wed, Sep 15, 2010 at 3:38 PM, James R. Coplin <james at ticalun.net> wrote:
> What I heard back from FPE express is that the tool is not tapered but a
> trapezoidal shaped tool with a max cutting diameter of .2mm.  However,
> tolerances for the machine and the bit work out -0mm to +0.2mm on top of the
> bit width.  Based in the panel I have from them, I would say assume 0.4mm is
> going to be the line size.  This makes finer detail fairly difficult to
> achieve.  On my Modcan format panels that I make it is difficult to get the
> text large enough to be legible at .4mm stroke widths on the dials and minor
> labels like around switches etc.  Just FYI if you are planning on making
> panels with FPE.
>
> James R. Coplin
>
>> -----Original Message-----
>> From: port23.co.uk at googlemail.com [mailto:port23.co.uk at googlemail.com]
>> On Behalf Of julian fincham
>> Sent: Wednesday, September 15, 2010 3:49 AM
>> To: James R. Coplin
>> Cc: synth-diy at dropmix.xs4all.nl
>> Subject: Re: [sdiy] Frontpanel Express line detail
>>
>> FPD simply states "Engraving tool - 0.2mm" but its not at all clear
>> what this actually meens -
>>
>> Does it meen that the line should be 0.2mm, or does it meen that the
>> tool is 0.2mm?
>>
>> And then it gets more complicated - if the tool is 0.2mm, what does
>> this actually meen?
>>
>> Cutter geometry is not as simple as simply stating a width - the
>> truncation (the width across the flat on the tip of the cutter) can be
>> one widh, but even this wont tell you the line width, as the angle of
>> the truncation can change, the clearence angle can change, not to
>> mention the cutting angle its self.
>>
>> And, once all this is done, with a V cuter, if you plunge the tool
>> deeper, the line is going to get thicker regardless!
>>
>> In short, i have no idea what FPD meens by 0.2mm, but you are possibly
>> better to use any numbers as a guide rather than some absolute.
>>
>>
>>
>>
>>
>> At this point, of course, i have to plug my own work -
>>
>> http://www.thebeast.co.uk/cnc/
>>
>> ; )
>>
>> Incidently i grind the cutters i use myself, and use different geomery
>> for different jobs/effects/finishes/metal types, to get the best
>> visual effect.  I find i get better end results this way, than simply
>> 'painting by numbers'
>>
>> Indeed this -
>>
>> http://www.thebeast.co.uk/cnc/DSCF4271.jpg
>>
>> is one of my favourite examples.
>>
>> Julian
>>
>>
>>
>>
>>
>>
>> On 14 September 2010 16:06, James R. Coplin <james at ticalun.net> wrote:
>> > I noticed in my last panel that despite my printed proofs and having
>> > everything stroked correctly the lines in my panel are decidedly
>> larger than
>> > what appeared on my proofs (even those printed from their design
>> software).
>> > I set the project and graphics up to use the .2mm engraving tool
>> throughout
>> > and all my text etc. I converted to curves, removed the fill, and
>> stroked
>> > the curves to .2mm with joins and endcaps set to round to match the
>> tool.
>> > Theoretically, what I was seeing in my proofs and on the screen
>> should have
>> > been what Frontpanel Express delivered.  Instead, it appears to me
>> that the
>> > lines are more like .3mm-.4mm in width.  Anyone else have this
>> > issue/observation?  My panel was black with no infill.  Does the tool
>> have a
>> > taper that with infill the text might have been sharper?  Just
>> wondering how
>> > to adjest before I send off my next panel as it is an expensive
>> learning
>> > curve.
>> >
>> > James R. Coplin
>> >
>> > _______________________________________________
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>> > Synth-diy at dropmix.xs4all.nl
>> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>> >
>
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