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File conventions

Fiducials

All professional drawings, without exception, will include at least two Fiducial points. Standard Exeter Laser Fiducials are available as the EL Fiducial.dxf

The EL Fiducial is two concentric circles, one 5.000 mm in diameter, the other 10.000 mm in diameter, with a 12.000 mm long cross hair extending 1.000 mm outside the outer circle, and a 2 mm high "X" to indicate the X axis, and a 2 mm high "Y" to indicate the Y axis.

Fiducials are always placed outside the work area, at the edges / corners of the design.

You should always include TWO (unedited) EL Fiducials in each of your drawings / designs, because;

  1. They provide a reference point for scale.
  2. They provide angular orientation information.
  3. They provide "looking at it from the top", not flipped, information, which can be especially important if engraving reverse sides / mirrored layouts and so on. The laser will always work from this "looking at it from the top" side of the material.
  4. They provide a reference point for aligning multiple layered objects exactly in the X Y plane.

With two EL Fiducials on two of the corners of each drawing / design it is flatly impossible for anyone to ever be confused about scales, or what angles some things are at, or whether you are looking at it right side up or not, or whether the various layers of a multi layer design object will line up perfectly.

In a perfect world, you should always put your fiducials on a layer of their own.

We, and everyone else in the engineering trade, will always assume that the fiducial shown is looked at from the top as shown by the image on this page.

We, and almost everyone else in the engineering trade, (except PCB manufacturers etc) will always delete / not print / cut / mill / engrave / these fiducials from the output job sent to the machine.

If your design uses fiducials which you want to have included on the output product, for ease of lining things up for assembly, or even as part of a logo or design, please ensure you use STANDARD fiducials, which means ONE circle, not two concentric ones, and no X Y text inside the outer circle... this way we, and everyone else in the trade, will know they are a part of your design that should be included in the production job.

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File naming conventions.

I, and almost everyone else with a clue, will love you if you have a file naming structure such as;

C:\MyDesigns\Enclosures\RaspberryPi\2014\07\17\ABCpienc-v0_1.dxf

Where the actual file name itself, ABCpienc-v0_1 means ABC for your initials, pienc for Pi Enclosure, and -v0_1 for version zero point one.

The reason is simple enough, the file name all by itself uniquely identifies it, because unfortunately we live in a world where people have computers full of folders called "New Folder" that are themselves nested inside trees of folders called "New Folder" and when you finally get to the individual files they have totally unimaginative names like "My Pi Enclosure.dxf"

Not only does this lead to the inevitable case where the machine has two jobs queued up with exactly the same file name, but one wanted 5 copies and one wanted 50.. now, which was which... hmm.. but also it doesn't tell us or anyone else which file belongs to Joe Smith and which one belongs to Fred Brown, nor does it tell us anything about which version of the drawing or design this is, and that one *always* raises it's head sooner or later, nobody, ever, got their drawing / design right and perfect first time.

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DXF files

Here at EL we like .dxf format files.

We like them because they are the industry standard, and because they are the industry standard, they leave very little open to chance or individual interpretation.

If, either at present, or at any point in the future, you are designing something that may well involve some other components, or some other supplier or engineering shop, or some other manufacturing process, then .dxf is the file format to use, every time.

For CAD work we here at EL like Rhino, so if you want to send us stuff you can send it as Rhino 3DM files or STL objects instead of DXF if you like, by prior arrangement.

From the above line you can probably tell, dxf is a CAD format really, as opposed to Corel which is an artistic / drawing format primarily, and it may well be the case that what you are designing is much better suited to being created in an artistic / drawing software package, and it is also true that many lasers and other devices can accept many of these "specialist" formats, such as Corel files, HP plotter files, GHS part maker files, etc etc, nevertheless, dxf still reigns supreme as the industry standard lowest common denominator file format, so even if you prefer working in a drawing or artistic package, when it comes to sending that data to anyone in the field of engineering or digital production, it is always a good idea to consider sending it to them in a format that they are used to, which will be dxf at the very least.

Our other metalworking machines such as the CNC mill and lathe etc all operate on NC, G-code file generated by the tool path software, and the tool path software all accepts input of dxf format files as a lowest common denominator... being both application and platform independent.

This is one of the reasons we provide some useful freeware trial ware apps in this section.

Incidentally dxf files are by their nature eminently suited to compression in archives such as zip or rar. Archives are a very useful way to bundle all the files together for a single project that relate to that project, documents describing the project, dxf files, image files, CAM generated models, you name it, and we welcome anyone choosing to give us a whole bundle so we get an overview rather than just the basic design and nothing else, if you so choose.

None of the above should give you the impression that we have any problem at all with someone who, for example, has only ever worked in Corel Draw, or Google SketchUp (great free models) and has no plans to ever work in anything else, and just wants to send us the native default file format for that application. If what you do works for you, that's all that matters.