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Will more than two decimal places cause trouble for milling and engraving?
Hi,
I am working on a design that also gives the possibility of small letters being engraved instead
of being silk printed, using milling cutters with a diameter below 0.2mm.
Even though any dimensionn of the parts is "spot on" (i.e a knob hast a diameter of 18.0 mm
or a cutout has 120.4x30.4mm) the line withs of the engravings are not.
I designed and measured the typos using two decimal places.
So the desired line width was beteen 0.58 and 0.38mm.
But switching to three or four decimal places
while using the measure tool revealed that the line width is not spot on.
Could be 0.3812mm or 0.3805mm.
Now, the letters are just decorative. Nothing has to fit or pair mechanically
But I am worried how a CNC machine will deal with data that has four decimal places
instead of two or only one. (It will be probably a Datron Neo)
Should I rework the line width? Is there a possibility to "throw away" the last two decimals?
Because reworking every letter would be really PITA...
All the best,
Herbert
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The CAM ain't gonna care. Run it!

Seth Madore
Customer Advocacy Manager - Manufacturing
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Thanks, but could you explain why? Does it automatically tranctuate the third, fourth etc. digits?
Also will a CNC-machine try to faithfully reproduce any edge and curve,
comparing milling position to desired data, observed by the worker. So he would have to
be told whar can be negelected, which could produce errors...
All the best,
Herbert
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CAD/CAM systems really don't care what you specified a feature to be, via dimensions. It goes on actual positions and size of part/feature. If it's splitting microns, it will round out to 3 places, if in inch, it will round to 4 places.
Regarding your second question: A CNC is a dumb machine. It will do exactly what you tell it to do. The responsibility lies with the programmer, through the use of proper selections and setup/operation definitions, to feed the CNC good data.

Seth Madore
Customer Advocacy Manager - Manufacturing
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Thanks! Uhm-I guess I will rework to play things save.
There is no way to round a part to two or three decimals in Fusion360 ?
Maybe through export and re-import?
There is also the minor problem that the lettering for engraving was
done in awful TurboCad Mac Pro. Now, in Fusion the engraving is cut out using the Combine Tool
But it looks to me that Turbocad used too many faces to describe the curves and fillets of the letters
How can I simplify them to a single curve in Fusion...?
All the best,
Herbert
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Without seeing the file, I really can't point you in the right direction.
File > Export > Save to local folder. Return to thread and attach the .f3d file in your reply

Seth Madore
Customer Advocacy Manager - Manufacturing
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Thanks for the offer! Now I started to design letters from scratch - everything is done by
starting with boxes that have basic sizes like 3.18x3.38mm. Line widths are 0.38mm.
I know I can use typos for this but I want defined values and rather love to "carve" the letter out of the box.
Later the letters are placed in a defined distance (Mostly 1.02mm) and combined to one body using a new box.
After this step measuring with more than 4 decimals suddenly shows deviations.
I.e. the y-position of the letters did show no deviation after they were designed and aligned, measured them with 8 decimals.
But after combining them the deviations appeared beyond the 5th digit.
I had to move the letters by the deviation and re- position them by the desired value, then re-combine them
This is really strange, as I am working only with two decimals in my design anyway!
And of xourse I expect the lower decimals to be zero as well.
Same with moving, mostly only one decimal is needed for positioning and is entered manually.
But it seems that also moving causes deviations in the last three decimals.
I attached a file with the corrected letters as well with the deviated positions.
A body, originally being part of this file, but too big to attach. The body has also strong deviations when measuring
with more than 3 digits, what I did for months. Also this body never needed more than 1 decimal in 90%
of all steps.
Just for reminding: The origin of the document was a .sat import from TurboCad Mac Pro.
It was reworked hundreds of times after that in Fusion360 but maybe a sat-import, even hundreds of versions away in the past, might still cause the deviations when modelling? Like that little - long forgotten and deeply buried
line of code that makes robots go berserk in "Westworld"...?
All the best,
Herbert
Fusion