Basics Questions

Hi everyone,

I was a graphic artist for a few years so I'm familiar with design programs like Photoshop and Illustrator. I'm trying to get some metal pieces cut out with a waterjet and they need the format in a CAD file. I recently got AutoCAD 2011 on a Mac and thought I could figure it out. I was wrong. I've watched some videos online but I don't have a good enough understanding of the basics to figure it out. Would anyone be willing to work with me a little? I'm sure we could work something out regarding payment.

Thanks,

Jamie

Just what are you trying to work out?

Waterjet? Do you know what file format is required? Could it be done with a DXF file?

I'm pretty sure we have had questions of this same type in the past.

Basically I have a few designs as Illustrator files that I need to either import or recreate in CAD. They aren't very complicated.

Waterjet is basically a saw that uses high pressure water to cut out predetermined patterns. I'm assuming that the file can be any format that AutoCAD can read.

Do you know if anyone was willing to help?

Are they plans and sections? Or is it a 3D model of the metal peices that you need?

I was thinking 3d models but I'm not entirely sure.

I assume that it is 3D that the Waterjet contractors will require.

I won't be much help to you because my version only uses 2D.

Hi everyone,

 

I was a graphic artist for a few years so I'm familiar with design programs like Photoshop and Illustrator. I'm trying to get some metal pieces cut out with a waterjet and they need the format in a CAD file. I recently got AutoCAD 2011 on a Mac and thought I could figure it out. I was wrong. I've watched some videos online but I don't have a good enough understanding of the basics to figure it out. Would anyone be willing to work with me a little? I'm sure we could work something out regarding payment.

 

Thanks,

Jamie

Jamie, I can help in a few ways. First, lemme try some info that I think will help you coming from an artistic background to technical drawings. I use CorelDRAW, Photoshop, Illustrator, AutoCAD, and a few others. My strengths are in CorelDRAW and AutoCAD, not so much with PS and Illustrator. I have built my own CNC Plasma table and I design and cut parts using CAD and the table. I think I can help bridge what may be a gap for you (it is for me, but going in reverse). With Illustrator and Photoshop (what work I've attempted to do) it seems that most of what you see on screen is just an image, not objects (again, this may be poor personal knowledge on my part). That is, you cannot just grab a person's face in a picture...it's not an object, it's just part of the picture. With CNC anything (plasma, laser, waterjet, etc.) you'll need clearly defined objects (squares, circles, arcs, etc.) which, in the CAD software you can just click on one part of the object to select it...each part is an entity. There is (to me) a very big difference in paradigms between artistic drawing and technical drawing.

So...learning CAD...this site has tutorials. I've used the ones at MyCADSite (google that..the URL is odd for good reason which you may or may not take the time to find out why). Regardless, I found them first and used them...but I've used the ones here, also...to learn AutoCAD. Play with them, they will help.

The basics are these: first, artistic stuff will often be in the form of JPEG, BMP, GIF, etc. which are raster graphics or bitmap files. CAD drawings are vector format (exclusively, I think). Imagine drawing a smiley face by placing checkers on a checkers board. The face is simply little dots in a pattern. If you try to make the image larger or smaller the computer has to guess at which dots should be filled in and which should not. Raster/bitmap graphics do not scale well (grab a JPEG, PNG, other web graphic and use PS or Il to make it 200% size and you'll see it pixelates...looks blocky. With vector graphics the file doesn't store a sequence of colored dots but rather instructions for how to draw a shape. For instance, look at the perimeter circle of your smiley face. Instead of a sequence of filled/unfilled dots, a vector format will instruct a program to (making up an example here) draw a circle at the center of the drawing area with a certain radius or diameter (with relational size information to the drawing area, in some instances), with color and other attributes (like maybe line width). Now, if you render the file at 1 inch wide and 1 inch tall, the circle is perfect...the program goes to the center of the square inch (1x1) and then draws a circle with the specified radius or diameter in relation to the drawing area size...not dots guessed at. Now, if you blow that up to 1 mile high and wide, it's still the same circle, just bigger. Vector graphics scale and, to put it simplistically, raster/bitmap graphics do not.

Now, back to AutoCAD. I have used CorelDRAW for years (off and on, never professionally). I'm pretty good with it but I decided to try to learn AutoCAD to do more complex and larger drawings (I design and build trailer-mounted smokers and other metal works...google LeisureMetal...the site's not done...but it's got some pics). At first, AutoCAD seemed harder to use. After the tutorials and some practice I prefer it to CorelDRAW and use it for all my technical drawings even though I used CorelDraw since version 3 (not X3, 3) and I've only used AutoCAD for 2 months. The thing that, in my limited experience with PS and Il, is the most different between the two types of drawing (and drawing packages) is that each item is an object. A square is an object which you can select by clicking on any part of it. You can scale it (make it larger or smaller) by adjusting textual properties and get definite results which are just as crisp and clean as the original (unlike sizing/zooming in on a photo/artistic image). Circles, arcs, lines, rectangles are all objects with properties you can adjust.

Now, for actually cutting metal: (and this is my experience but in no way meant to be preaching like I'm God Himself here...others may disagree or know better than I) MOST common machinery you'll run across for waterjet, laser, or plasma will do just X-Y axis and are referred to (sometimes) as XY tables. That is, the table moves a torch (water/plasma/laser) left and right and front to back. Yes, they move up and down to allow for thicker/thinner materials, but the Z is not really at play (like an engraving table could do). And these torches will move (again, this is usually, not always) in a fixed vertical orientation which is usually perpendicular to the workpiece. That is, if the cut were perfectly made, the face of the cut part would have a 90 degree angle to the vertical sides (with the vertical sides being the perimeter of the cut part and as tall as the thickness of the material). To clarify...if you cut a circle (imagine a dime) from some material, the face of the dime is the part (circle) you want cut out and the vertical side I'm referring to is the thin, lined sides that are as tall as the thickness of the dime. Going further: when you get parts cut on *most* CNC torch tables (water, laser, plasma...even oxy-fuel) it's like cutting a drawing from a sheet of paper...there is no consideration of the angle/profile of the vertical sides...the sides are square (in theory...in practice it depends on the process (plasma tends to give not-perfectly square cuts from the top of the material to the bottom)). Some machines are capable of doing beveled cuts where the vertical sides are at some angle by design...like cutting a cone out of a flat piece of metal. But *most* will only do the same as cutting the drawing from a sheet of paper...no consideration of the profile of the sides.

That said, you should not need 3D drawings to produce parts because *most* jet cutting machines lack the axes necessary to angle the sides and, furthermore, are designed to cut *through* the material. Back to the dime...the face of the dime has higher and lower areas. An engraving table with 3D capabilities could engrave the surface of a dime, moving up and down as needed to create the relief/3D appearance of the face. A torch (water, plasma, laser, oxy-fuel) is designed to cut through the material and the only consideration for the third dimension (up and down or Z) is to make sure the torch doesn't hit the material. If someone asked you to draw and then cut a circle from a sheet of paper you would not need a 3D drawing to do so. Cutting a shape from some material with an XY table is like cutting a shape from a sheet of paper with scissors...you only need left to right and front to back (top to bottom on the sheet of paper). 2D is fine. I've sent a number of parts out (before I built my plasma table) and never had a request for a 3D drawing of the parts. Even if you're designing, let's say, a box made of 6 pieces of steel cut from a flat sheet, the cutters probably don't want the 3D version...because they'd have to do the work of making it into 2D shapes (6 of them).

You have AutoCAD, great. Do the tutorials, from the beginning, and don't go to the next one until you understand the first one. You can also check out DraftSight, a free (for individual use) clone of AutoCAD.

I'm trying to finish a large smoker project for an oilfield services company right now and I'm just a one-man shop here but I'll do what I can to help. I've also not used this site much (the forums) so forgive me if I'm sluggish to respond until I see how I get notified by the site about replies...and as I try to finish this project. Like I say, I'll try to help you. I'm no AutoCAD expert but I've toddled a few steps in your shoes and I understand a bit about CNC part cutting and the mating of drawing the parts to producing the parts.

--HC

If the Illustrator files are vector lines, then you can just select everything and export it as a DXF. Then open the DXF file in AutoCAD so you can scale them to the size you need.

HCb: While your dissertation was appreciated nowhere within it did you tell us or the OP what output (from AutoCAD) would be acceptable to cut the part on a waterjet. I "guessed" at DXF. SuperCAD's response seems to verify that fact. Care to comment?

DXFs are what waterjet programs normally read. I know because we have a waterjet at our facility. I also am a Graphic Designer that was thrown into the CAD pool.

Jamie Moore, do what others have told you, export your file (what you want cut) as a DXF and then use the scale-reference command to adjust the work to it's correct size. Open your file in Illustrator - select all of the artwork - take note of OA height or OA width - export DXF to CAD - draw a line, using the dimension previously notated in Illustrator, horizontally (for OA width) or draw a line, using the dimension previously notated in Illustrator, vertically (for OA length) - you'll notice that your line will be quite smaller than your shape - select your artwork (not the line you drew) - click on the scale command and hit the down arrow key until you come across reference - click on the bottom (if you've drawn a vertical line) and then click on the top of the artwork and make sure you have OTRACK selected at the bottom of your AutoCAD screen and track your line to it's vertical line. I may need to include screen shots to further illustrate how this is done.

Wow. You guys rock! Let me play around with it a little and see what I can come up with. Thanks for everyones time.

Here's the screenshot step-by-step:

The forum will only let you put 12 pics at a time. Here's the 13th screenshot:

There are 2 ways of doing this.

The first is shown above with exporting the original vector file as a .dxf file, importing it into ACAD and scaling it.

If a vector file is unavailable for whatever reason, you can import a raster image (jpg, jpeg, gif are common ones) and you can trace a straight line through the image (an example would be one of the lines of the star shown above). From here you can simply use the reference scale shown above on the image and the line and continue tracing. I will upload some screenshots when i get home from work if needed.

We used this 2nd method back in highschool to make vinyl decals for ourselves and what not.

Note: Almost all plasma/waterjet/laser cutters use dxf files. Any other file type they would have almost certainly asked for specifically.

In AutoCAD 2011 or later I would use Autoconstraints to quickly tidy up the import before scaling.

HCb: While your dissertation was appreciated nowhere within it did you tell us or the OP what output (from AutoCAD) would be acceptable to cut the part on a waterjet. I "guessed" at DXF. SuperCAD's response seems to verify that fact. Care to comment?

Hey, ReMark, that's true, I didn't mention the filetype. However, in all fairness, the OP said he was told he'd need a CAD file but didn't ask what that was but rather mentioned he'd been working with AutoCAD and stated he'd not been able to figure that out and that he came from a graphic artist background. I've tried to walk between the two different types of drawing and thought I could offer my personal experiences which might help the OP in doing the same. The biggest difference between graphics art work and technical drawings (in my opinion) is the difference in paradigms; objects versus a canvas of indistinct/non-descript/amorphous shapes and colors. Having tried to work with PS and other graphics programs that are more painting programs and which do not work with objects much (photo editing, for instance), I felt it would help the OP to try to give background on the differences I see. That's my personal experience and it is not authoritative, but I hoped it would help the OP get his head right with how technical drawings work (or how I think they work; I'm no expert). Once that hurdle is cleared (and it may not be a hurdle for him or others but, for me going backwards to PS it has been...it's frustrating to me to click on an object but it's not an object and I cannot just select it), he may have greater success with AutoCAD (and other technical drawing packages). He then stated he watched some videos but did not have enough understanding of the basics to figure it out. When he asked for someone to work with him, I took that to mean he wanted someone to help him learn AutoCAD, starting with the basics.

It's embarrassing to admit now, but, coming from CorelDRAW, I was used to clicking on a part of an object, it would be selected, and then I could drag any part of it to move the object but, when I tried to learn AutoCAD, I couldn't move an object at all...selecting an object and then dragging a handle would just distort the object (try it with a square or a circle and drag a handle other than the center). Yeah, it's child's play to move an object in AutoCAD...when you know to use the move command or click a handle and hit Enter...but to just pick it up and try to use it, it can be difficult. Or maybe I'm a huge idiot. But I thought I might help the OP get grip on the basic paradigm (as I see it) which might get him pointed in the right direction so when he views a video or goes through a tutorial the most rudimentary concept of dealing with objects with properties would be understood...a concept which is taken as self-evident to some when they know it, but not necessarily really self-evident at all when you don't. Try explaining electronics basics to someone and tell them that electrons move but current comes from the positive terminal of a battery...until you explain the difference between electron flow and current flow, it's confusing as sin...'wait....the electrons move...but the positive terminal supplies the current?'

I in no way meant to disregard the letter or intent of his request for help. Just trying start of with the really basic stuff, the stuff the rest of us who do technical drawings (and y'all a lot more than me as you know from my post about the trusses) take for granted.

Anyway, yes, DXF is the file format I use to feed into my CAM software (the software that turns a drawing into machine code), and the file format that I have provided to other shops before I had a CNC plasma table and for other products for which I have no mechanism to create (like vinyl graphics). DXF files have been accepted from me by: my own CAM software (SheetCAM TNG), my vinyl guy (who farms some banner work out to Fellers, a large supplier of sign materials and banners and more), and at least four other shops running CNC equipment (mills, plasma, and laser). I wouldn't say I'm an expert, but I've done a fair share of design work for 2D cutting in metal and vinyl and DXF has always been accepted if not specifically requested.

--HC

bbankston,

That seems to have worked. Thanks for the pictures, they really helped. I'm getting with the manufacturer later this week. Now, time will tell.

Just what are you trying to work out?

 

Waterjet? Do you know what file format is required? Could it be done with a DXF file?

 

I'm pretty sure we have had questions of this same type in the past.

Most all shop (automated) machinery uses *.dwg input. Milling machines use x,y & z, the cutting equipment only requires

x & y. The machinist sets speed, table jigs, tooling.

No problem, Jamie Moore. I've done this technique hundreds of times.

Hey man. I wanted to let you know that worked like a charm. I should have the finished product early next week. Thanks again for your help. Happy Holidays.

Jamie

The forum will only let you put 12 pics at a time. Here's the 13th screenshot:

 

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