The Ship Model Forum

In that case you better try http://www.etchworks.eu/

These guys in the states. Very helpful, especially their artists. Not sure if its considered a downside to some, but they mainly deal in large sheets; (12" x 24" or so). I draw everything myself, so the art cost is nil, but after the tooling, shipping, and sheets (minimum 3 or so sheets), you're looking at a $500 USD bill (depending on material, but that was with .007" stainless steel.)

http://www.decorativeetching.com/

Dave, what etcher are you using? Darren

I was given my copy of Corel Draw and have stuck with it and was taught a few tricks using it, so I prefer it, but hadn't had to fully worry about the outlines before. I contacted my photoetch company and they said to turn off the outline and only draw the fills, so I get the fold lines I want. I was however told anything I want a full etch on to add a little to make up for the cusping effect.

I draw with 6 decimal place precision and I've only had Corel Draw crash on me a few times; most of them were because I forgot to install my new graphics card driver when I got a new card, lol.

Now that 3D printing is taking off, I will need to visit with CAD software and who knows I may use it for etching too if I like it, but like any tool, it will take time to fully learn how to use.

I appreciate the replies here.

Sorry, I wasn't trying to correct you, I was just commenting in general

With some of the more complicated designs I really want the measurements to be exact; no decimal round-offs or I get confused... Sometimes I do correct measurements to whole 0.1mm intervals. Most drawings do not even align up well so some interpretation is always allowed. I'm not so skilled in Illustrator but perhaps drawing may work just as well. In Rhino can you have folding and the like but I haven't started using Rhino seriously yet...

EJ, I should have made myself clear, I wasn't suggesting that Corel was a CAD program, only highlighting some differences.

I learned AutoCAD way back in the 80's. Wasn't impressed with it. Tried again in the 2000's, still didn't like it. I've been using CorelDRAW for over 20 years. I won't say it is perfect, far from it, but I find it very easy to use. I like it better than Illustrator, probably more because of familiarity than any real advantage. The biggest thing for me is drawing WYSIWYG. I like being able to draw a square in one motion, fill it with black or a colour, turn it on or off via layers, copy OR duplicate it with same properties and know it will print as I see it. I've always had a problem with CAD programs that print after a line, to a line and you don't see what you've done until it's printed. I also like being able to switch from line view to full colour view with one click. Like I said, probably more a familiarity thing than an actual function of the program. I'm trying to learn Rhino3D and am running into the same issues. I just don't like how things are done.

As for accuracy, I draw to a half thou, which in my books is plenty for photo etch. When the chemical milling (photoetching process) is done, a second here or there can alter the outcome by that much.

So lets discuss the processes. Originally, Printed Circuit Boards were designed by people sticking black tape onto clear acetate 3 or 4 times the finished size. Then it was photographically reduced onto a negative or positive film (depending on the type of resist chemical), This had the effect of reducing any errors or roughness in the edges. Then the film was laid on a board with copper on it coated with photo resist and exposed to UV light until the resist weakened, allowing a developer to dissolve the part not wanted. After this the board was then dipped in Ferric Chloride acid, eating away the bare metal until you had resist covered traces left that would carry the current between board components.

Advances over the years included a resist film that could be stuck to the boards, instead of a liquid spread onto it to cure. Conveyor style spray washers to control exposure time of the metal to the acid, double sided boards, multi layered boards, CAD printing of the artwork to be photographed, then CAD printing onto the film and finally CAD printing of resist directly onto the boards. There were some other variations along the way, but these are the major steps we're interested in.

The process of etching metal without the substrate needed for printed circuits is essentially the same and is often referred to as chemical milling. Brass is generally used for PE because it's easy to manipulate and takes glue and paint well and is also solderable. Stainless is used when you want strength, but doesn't hold paint very well. Beryllium Copper is also used at times.

When I started doing my own PE for my kits, I preferred drawing in Corel since I was skilled with it, however, over the years certain technologies have disappeared or are difficult to find. One of these essential to the traditional method of PE making is the large format film cameras used to make the negative or positive films to use in exposing the resist on the metal. In the past, you could print on paper and have it photographed. Now that most places have gotten rid of the their cameras, you have to print directly onto a clear sheet with a special printer. Some places don't even like that as the sheets are thinner than they prefer to work with and could cause issues during the exposure. Most etching places are only set up to take CAD files and use these to print their own films or directly onto the metal. CAD programs set up for printing a little differently than Corel.

My preferred method is to export my file into a PDF, send it to a graphics place that still has a film printer and then have that film sent to the etcher. There are many other ways to do this. I like it this way as I know that what I see in the PDF is exactly what will be printed onto the film and nothing in the original file will be altered or misinterpreted.

Corel as been able to handle pretty much anything I throw at it size wise, but it has been known to crash on occasion.

Darren

Coreldraw or Illustrator aren't really CAD programs but graphic programs; I use Autocad for my etch drawings because it is so much more accurate. However, Autocad is absolutely awful at filling in the blanks and then I use Illustrator. Illustrator doesn't allow me to zoom in much (default settings?) and I find it awful to do any real drawing work (I really like the command line of Autocad for giving orders). I have no experience with etch drawings in Coreldraw, but has their programs have deteriorated significantly I have no inclination to try; Coreldraw is too slow and crashes upon opening of large images (when I use it). Might just be me

Anyway, I use Autocad to draw the exact outline of certain parts and have separate layers with lines that need a thickness. So, my outline thickness is always zero so that the control points of all surfaces are really the outline of my parts; otherwise you need to draw everything a bit smaller. When going to Illustrator, I do have to set the line thickness in all layers with filled objects to zero. When I need a fold line, I just split the part over the fold line by one plate thickness in the CAD file. If the fold line is too thin due to the line weight of an object than the part will not fold well. You cannot rely on the manufacturer to play around with the artwork so you need to send it to them 'as is'. Which reminds me: always ask them to send you the PDF before producing (especially with a new producer). Even when they only open up the artwork for inspection some properties are sometimes changed (Version problems?). Sending in your own PDF is probably best, should that be possible.

It will depend on how you have it printed for etching. CAD programs use the lines and fill inside when printed (or something like that.) I print out PDFs so the outline will show up on the films. That will change my dimensions, so I always remove all outlines. If your etcher prints direct to the brass, it may not be an issue. Talk to your etcher.

All,

I've been trying to draw parts on my own using guides I found online, but they are not specific to Corel Draw; thus my question -

I'm drawing parts on a .004" thick sheet and my sheets have fold lines in them. Do I need to draw all of my shapes with NO outline? Corel Draw users know that an object is made of an outline and fill. I'm finding the outline adds about .006" extra thickness to my fill (which is correctly .004"). Is this a problem or just exaggerated by Corel Draw when I'm zoomed in all the way and moving my cursor across the fold line object and looking at the X value be .1 in length instead of .004...

Thanks for your help!
David Friedlander