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JRP

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#31
Spindle cap.jpeg
 

Ray C

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#32
Bill,

Why?

Ray
 
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#33
Why what?????
 

Ray C

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#34
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#35
It takes me too long to read CAD prints. They are not the same as hard drawn. Sometimes things cannot be seen.I don't really want or need to learn a CAD program just get a better understanding of it.
 

Ray C

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#36
It takes me too long to read CAD prints. They are not the same as hard drawn. Sometimes things cannot be seen.I don't really want or need to learn a CAD program just get a better understanding of it.
Gotcha... Most CAD programs can create traditional 2D projection drawings but many people these days don't bother.

Question: When I show you a diagram like this one, does it make sense? If not, I'll spend time this weekend with a write-up about how and why it looks this way.

SpringSupport.JPG

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#37
No Ray,it does not
 

Billh50

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#38
I think I understand what Billy G is saying.
Most people send or post cad files showing either just 1 view or sometimes a partial view. Where as a hand drawn print usually shows 3 views. Therefore it is easier for some to visualize the part with all 3 views.
The view Ray posted can be confusing to many. Even some of us that do use cad.
 

Ray C

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#39
OK. I get it. I'll explain why this is happening and going forward, when I post diagrams, I'll try to show more context. I could draw traditional 2D drawings but, it's an extra step (and a time-consuming one at that).

I'll post here later today and tomorrow.

Ray
 
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#40
You cannot take for granted that people will know what you are showing. For the most part when you do and they don't understand they will not come back or ask questions. They do not wish to show that they do not know.
 

Ray C

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#41
Here is my preferred CAD program (Called Alibre Design Expert).

This is the blank writing area that's currently showing an X-Y coordinate plane.

EmptyScreen.JPG



Let's say I want to make a grinder hub part. The program gives me drawing tools and I start by just making the profile of 1/2 the part. It is shaped like the letter L backward.

ProfileOfPart.JPG



Next thing I do is use the tool to add dimensions. Notice that I did not put shaft part right on the Y axis. I specified that it is .125" away from the Y axis because I later want the ID of the shaft to be .250". In this example 1/2 of the base is 1" diameter. The base thickness is .3" and the sidewall of the shaft part is .250".

ProfileWithDimensions.JPG



The program will allow me to revolve that profile and extrude material as it revolves. Here is the setup where I'm telling it to revolve that L shaped part around the Y axis.

RevolutionExtrudeSetup.JPG



When I press the button, it revolves the part and shows it shaded. It's still shown in 2D but the shading makes it look more like 3D.

RevolvedAndShaded.JPG


I can go back and edit that L profile and modify the dimensions if I want to. When I go into that edit mode, it looks like this where the profile is shown on top of the revolved/extruded part.

EditProfileAfterRevolve.JPG


Here is what has you screwed-up. Sometimes I am guilty of zooming in on the dimensions of the profile and you can only see the bark on the trees and not the whole forest.

Close-up.JPG


The program can show other views if needed like this:
3D-View.JPG

Is that clearer than mud?

Ray
 

Ray C

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#42
Also, once the CAD is finished as shown in post #41, the CAD program can produce traditional mechanical drawings. You see however, that is an extra step that many people (myself included) don't do. Later on, I'll show how those drawings are produced. In this particular program, it is very time-consuming and I usually have to start-over at least a couple times. I gave up on it.

FWIW, I took mechanical drawing in high school. It was called Engineering Graphics 101. I was good at it and whenever I hand-draw something, I always use that style. Most of my more complicated design projects start with hand-drawn sketches.

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#43
At least I can read those. LOL
 

Billh50

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#44
Ray,
The OP was that a partial view is not enough to comprehend what a part looks like. It doesn't matter if the part is drawn in CAD or On Paper. If only a partial view is shown then it is hard to tell what it is.
I believe that is what Billy G was trying to implicate.
 
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#45
yup
 

vtcnc

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#46
This is all fine but where did your initial info come from. This thread so far has not produced what I am looking for. I want to know where to start. Getting a program is a start for sure but it is not basic enough. Where is the 0 point for the person who knows nothig at all.

I always thought CAD was Computer aided drafting. It is not, it is computer aided design. Am I getting my point across yet??

"Billy G"
Hi Bill, I think I get what you are asking. You want a computer drafting program, not a computer design program because the former is traditionally the first thing one learns prior to the latter, correct?

This storied learning methodology of the old days is a rock solid way to create excellent draftsmen who could later become excellent machinist, or engineers, etc. Sometimes I long for those days...but I digress.

I graduated from a Vermont Tech in 1997. I believe that I was in the last (if not next to last) year of formal board drafting in my classes. I learned how to do drafting - plain and simple - yet a foundation skill for mechanical engineering. Other classes were aimed at design or engineering principles or machining. One can see how these logically build upon the prior skill. I think that is what you are asking for here.

If so, here is my take at an answer on where to begin as an extreme beginner:
  • You have to accept that various companies try to integrate several drafting, design and engineering functions and sometimes manufacturing functions into one package.
    • 2D only
    • 2D/with drafting
    • 3D only
    • 2D/3D
    • 2D/3D/drafting
    • 2D/3D/drafting/CAM
    • you get the idea...but with that understanding you can imagine that you need to get your ducks in a row on the following variables if you intend to focus on drafting:
  • If you intend to do drafting you should decide what your drafting standards are going to be because CAD programs utilize templates. Templates give you the desired consistency in the final output of your work:
    • linetypes
    • text formats
    • border styles
    • title block formats
    • sheet sizes
    • units
  • You should also learn about the different file formats available to you and the purpose they serve - they can sometimes paralyze progress when it comes to the following:
    • utilize the file for CNC?
      • engraving
      • 3D machining
      • 2D profiling
      • rendering/modeling/visualizing
    • utilize for sharing/viewing/markups with customers or partners?
      • what software will they view it with?
      • what software do they have and can they export to your format if needed?
    • utilize for printing?
      • if no engineering plotter, can I export to PDF and print?
  • Decide on a file structure and drawing naming convention prior to starting. You may have one now for your paper drawings and that may be good enough, but you will find yourself needing to search for drawings at a later date and it is different searching by keyword than it is by rifling through a drawing flat. Consider the pros and cons and imagine your self searching for drawings later like you do for photos on your pc now! I can tell you that my photo system ain't pretty!
  • If you are going from zero to one, i.e. board drafting to CAD drafting, then I would recommend that you understand a couple of key cad concepts:
    • cartesian coordinate system in CAD, no different than thinking like a machinist. This is essential if you intend to learn 3D modeling.
    • more importantly, learning the coordinate system will set you up for efficient and effective geometry construction even when you are 2D sketching or creating projections and orthographic views.
  • Geometry construction techniques in 2D CAD are a lot like board drafting. You will create construction lines and feature lines much the same way you do on the board. The difference here is that pencil pressure (light vs. dark line) is substituted for color, line types, line thickness, etc. Circles, arcs, polygons, etc. are all constructed using the same principles used on the board, just faster and more intuitively.
  • Also, you will find that finding line ends, intersections, bisections, tangencies, etc. are controlled by the mouse.
  • Annotations on the print are fully controlled like editing text in Microsoft word.
I don't think these things are very difficult at all for anybody determined to enter the CAD world especially at the 2D level. I actually agree with you about one of your prior comments, most of the shop work we do can be done on pencil and paper and there is no CAD needed and I find myself doing that more often as I sometimes just need a simple part made. But you will find over time that revisions to your designs, layouts, and having a record readily accessible and easy to change is dang near invaluable.

I think these are some of the things I would want a student to learn and establish in my class if I were teaching a beginner.
 

vtcnc

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#47
I think that is what you are asking for here.
And then I realized I missed your posts with @Ray C o_O

Yeah, if what you are saying is that by and large individuals who use CAD do not stick to accepted industry print standards - well my experience is that few people take the time to create really good prints anymore. I won't get on that soapbox.

Your OP though led me down a different path as if to ask what would be prerequisites to create good prints in 2D CAD...
 

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#48
I first learned CAD on a system at work about 18 years ago when I was doing thermal analysis. I don't remember the name of that one anymore, and it likely comes with a $10,000+ per year licence fee. For my personal use, I used varaious different versions of Turbocad. I switched to Fusion360 a few years a go, and would recomend it to anyone just starting out in CAD. I would say it would probably be much easier to learn than Turbocad was, just because it is much easier to use. It is also parametric (which means if you decide you want to change a feature on a model long past the time you created that feature, you can just go back to the operation where you made it and change a dimenions, it will recalculate the rest of the model to compensate). It has a capapble CAM program built in, as well as anlayiss capability, which is surprisingly easy to use. Most drawings of the kind of things that most machiniists are interested in are just a series of 2D sketches that are then extruded, lofted or revolved to make a 3D shape, then those are added to and subracted from each other to make the part you want. It also has a fairly easy to use drawing utility, so you can easily make dimensioned drawings to take to the shop. It can do movement as well as check for interference. Very full featured. Best of all, it's free to hobbyists, students and buisinesses that do less than 100k per year in sales. My only real worry is that the free policy could end with a change of management, but it would be worth paying a nominal amount for, and if they go crazy, I guess I can always go back to Tubocad (reluctantly).
 

magicniner

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#49
If it's just for viewing CAD drawings and models from others you may only need a Viewer, you only need the full CAD package if you want to edit, annotate or create your own work
 
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