3D cad design sequence

[Gordon]

I finally gave up on trying to extrude the 3D gear because I still cannot change most of the other things like bore, hub size etc. I have downloaded a 2D model and modified it in my 2D cad program and saved it as a DXF. The problem is that when I place the drawing it puts it out in space some place. Since it is not fully defined I have not figured out how to move it to the drawing origin.

 

[Gordon]

I don't handle either transition very well. I would be happy if they would go ahead and let us stay with "daylight savings time" all the time ...

The experts say that the body is better staying on standard time. For me I would just like to leave it alone. I can live with either one, just quit changing it.

 

[Jasonb]

You won't be able to change individual items like the bore or boss as if you were editing a gear you had modelled yourself as they are just imported as a solid.

So think of it as a purchased gear and sketch the things you would machine.

Want a bigger bore then sketch a circle on one face and cut-extrude through all
Want a smaller bore then draw 2 circles and extrude those to "sleeve" the existing bore
Bigger boss draw a bigger circle and extrude
Smaller boss circle what you want to remove and cut-extrude just like turning down the boss
Shorter boss just draw a rectangle with one edge dimensioned from the edge of the existing boss by how much you want it shorter and cut-extrude

I had no problem doing any of those things with one of the gears from your link imported as a STEP file. If you look at the image I posted yesterday where I made the gear a lot wider you can see the red sketch which was used to sleeve down the bore and there is a boss on the opposite side to the extrusion of the gear profile.

When I imported the file it was concentric to the Z axis and as the gear is a single part should not need moving further. If you want to put it into an assembly then just the usual concentric constraint of the gears bore and the face of a shaft will do.

 

[Richard Hed]

I finally gave up on trying to extrude the 3D gear because I still cannot change most of the other things like bore, hub size etc. I have downloaded a 2D model and modified it in my 2D cad program and saved it as a DXF. The problem is that when I place the drawing it puts it out in space some place. Since it is not fully defined I have not figured out how to move it to the drawing origin.

You are doing it the hard way. just use your import as a template. Extrude a circle, then make a single tooth (either the female part or the male part, it doesn't matter), extrude THAT, then use the circular pattern command. Make it simple. At least that is the way I would do it.

 

[Richard Hed]

The experts say that the body is better staying on standard time. For me I would just like to leave it alone. I can live with either one, just quit changing it.

If you are retired, you can get up and go to sleepa any time you like. As for myself, I am working part time and have to be at work at a certain time. I still get up at the same time as I usually do, only now the clock says 4:00 when I wake up. I just do interesting things till it is time to get my lunch together.

 

[johnmcc69]

You are doing it the hard way. just use your import as a template. Extrude a circle, then make a single tooth (either the female part or the male part, it doesn't matter), extrude THAT, then use the circular pattern command. Make it simple. At least that is the way I would do it.

That's pretty much the way I do it. I'll model a single tooth (It doesn't have to be fancy, but the geometry is pretty simple as are the tooth calculations.) & as Richard says, make a circular pattern of that tooth profile.

When you try to import all those segments from "Imported geometry", you may end up with an "unconnected" sketch (I don't know what it's called in different softwares), but, I know in my experience, I've spent a lot of time trying to close up & fix a sketch like that.

In Pro-E, I can "toggle" a sketch to show the interior sketch as shaded, or "filled", if it is indeed a closed sketch & usually don't have any problems. Does Alibre have something like that? Gordon also mentioned problems with the extrude direction not being able to predict the direction: Does Alibre have any kind of "Preview" feature that shows you the extrude before exiting the command?

I've usually had pretty good luck with the Rush Gear STP files, but I usually modify them exactly as Jason mentioned, but...I find it's just as easy to create the single tooth & pattern that. You can then take that a step farther & save a sketch (As its own "sketch" file, properly dimensioned & (ahem) Constrained, & use that tooth profile in any gear design). A caveat with that method may be regeneration times & file sizes, but depending (again) on your software, you may be able to "group" or "merge" all the teeth together or even save out your gear file as a STP file, import it back in, & then save that as your model file, it will then come in as one imported solid feature & not have to regenerate all the tooth profiles. If you're not happy with that gear, you can go back to you original gear part file (You didn't delete that right?) & make your modifications & then export it again as a STP. this method seems to work pretty well with model files that have a lot of patterns & complexity.

I hope this makes sense & helps.

You're doing just fine Gordon. Keep at it.

John

 

[Jasonb]

Yes Alibre does give a preview of the Extrude before you press OK, I this image I posted earlier you can see the light red outline which is the sketch and I have extruded that 2"

I don't use the single tooth method but the Pro version of Alibre does have a script for generating gears which is what I mostly use. F360 also has a gear generator.

 

[Gordon]

I certainly am learning a lot as I stumble my way through this exercise. I am finding that the cheap version of Alibre does have some limitations but it will work for my needs and I certainly am not going to spend $1000 for just my hobby use. One thing that I do like about Alibre is that it lives on my computer instead of in the cloud. I don't like the idea that my information is out there in cyberspace and if the company decides to suddenly start charging too much I can lose all of my work. I am not going to be designing stuff for the space station. I have already spent more time on this than I can really justify if I just want to design my own projects. I am able to design things with my 2D program. I just looked at the 2D that I have been using and found that I have been using that since about 1985.

 

[Richard Hed]

I certainly am learning a lot as I stumble my way through this exercise. I am finding that the cheap version of Alibre does have some limitations but it will work for my needs and I certainly am not going to spend $1000 for just my hobby use. One thing that I do like about Alibre is that it lives on my computer instead of in the cloud. I don't like the idea that my information is out there in cyberspace and if the company decides to suddenly start charging too much I can lose all of my work. I am not going to be designing stuff for the space station. I have already spent more time on this than I can really justify if I just want to design my own projects. I am able to design things with my 2D program. I just looked at the 2D that I have been using and found that I have been using that since about 1985.

exactly! If you are EARNING money as an engineer or designer, then the 1000$ may be justifyable but not if a hobbyist.

You've been using 2D since 1985? The Dark Ages? Before . . . CRUISE CONTROL? Befor the INTERNET? I'm surprized you survived. I thimpfks yhou will find that 3D, altho' you are struggling with it for a while more, you will eventually find that it is ACTUALLY EASIER than 2D!

I know that I can whip out a 3D a lot faster than a 2D and then use the 2D generate method to be MUCH faster . . . and easier as I've sed a score of times. Also, in Alibre, the dimensioning is a lot easier than AutoCAD. I learned how to put all my drawings for a machine in a single PDF also--that is a really nice function. I used AutoCAD 3D for many years, but now I don't bother unless for some need of great power which AutoCAD certainly has but like microsux, bloated and unnecessary.

 

[Gordon]

exactly! If you are EARNING money as an engineer or designer, then the 1000$ may be justifyable but not if a hobbyist.

You've been using 2D since 1985? The Dark Ages? Before . . . CRUISE CONTROL? Befor the INTERNET? I'm surprized you survived. I thimpfks yhou will find that 3D, altho' you are struggling with it for a while more, you will eventually find that it is ACTUALLY EASIER than 2D!

I know that I can whip out a 3D a lot faster than a 2D and then use the 2D generate method to be MUCH faster . . . and easier as I've sed a score of times. Also, in Alibre, the dimensioning is a lot easier than AutoCAD. I learned how to put all my drawings for a machine in a single PDF also--that is a really nice function. I used AutoCAD 3D for many years, but now I don't bother unless for some need of great power which AutoCAD certainly has but like microsux, bloated and unnecessary.

I started using Generic Cadd when it was on 5" floppy discs that required changing the disc for the next operation. I think that there were about five discs. I don't remember what each one was but I know that in order to add dimensions you changed the disc. About 1989 Autodesk bought the company because Generic was stealing their customers. They supported it for a while and then killed it and gave everyone a free AutoCAD light which was just a badly crippled version of AutoCAD. Some of the original developers then started Numera and came out with a newer version of Generic. After a couple of more ownership changes it finally ended up as Visual Cadd.

 

[GreenTwin]

I remember Generic CADD, and I seem to recall having a copy, although I did not really get into 2D as far as using it until about 1994.

Today's jet jockeys may not realize just how bad the screen/user interface was in 1984/1985.

There was no Windows on an IBM-PC or clone (although I did have Excel which had a windows run-time version that ran on top of DOS).

The interface was a crappy monochrome screen, rather small, perhaps 12", and low resolution, so very grainy.

They did have mice, but more often people used digitizer tablets with 2D back then.
I was never so glad to see the digitizer tablets hit the dumpster.
They were pretty useless in my opinion, but we had a lot of "digitizer-tablet huggers" who did not want to give them up no matter what.

You can see in this video just how bad the old DOS operator interface was.

I also used Multiplan, which was a DOS-based spreadsheet, with the same crappy DOS non-graphical interface.
Usable for sure, but clunky like an old Russian car, and with pedals instead of a motor.

 

[johnmcc69]

Wow.
I don't miss those days at all (Learning ACAD & using a tablet). I have to admit it did feel strange finally ditching the tablet (ACAD R13?), as much as how strange learning 3D was & not having the cross hairs on the screen.

John

 

[Richard Hed]

I started using Generic Cadd when it was on 5" floppy discs that required changing the disc for the next operation. I think that there were about five discs. I don't remember what each one was but I know that in order to add dimensions you changed the disc. About 1989 Autodesk bought the company because Generic was stealing their customers. They supported it for a while and then killed it and gave everyone a free AutoCAD light which was just a badly crippled version of AutoCAD. Some of the original developers then started Numera and came out with a newer version of Generic. After a couple of more ownership changes it finally ended up as Visual Cadd.

OMG--five inch floppys? I forgot all about those. Geez, that was BEFORE the dark ages. You are THAT old?

 

[stanstocker]

OMG--five inch floppys? I forgot all about those. Geez, that was BEFORE the dark ages. You are THAT old?

8 inch floppies rule! Hard sector too, none of that new fangled stuff from people who don't appreciate AO horn rimmed glasses and a good pocket protector! Got to boot that 360 or VAX from something when you IPL! I remember Generic Cadd too, kept me using vellum and t squares for a few more years it was so klunky

 

[GreenTwin]

You guys are New School.
I have an IBM word processor machine in my attic with dual 12" floppies.
(Or maybe they are 8", but they look 12").
Big frisby things.

I did not keep the IBM punch cards I used in school on the mainframe.
We have some dino-programmers here.
.

 

[Gordon]

Yes. I am that old (82). I started out with a Kaypro computer with CP/M operating system sometime in the 70"s with a single 5" floppy where you loaded the program into memory and then removed it and entered the data on the next 5" disk. Going to a PC where you entered DOS commands instead of a graphic interface was a big improvement. Computer use was never the main part of my business but I used a computer for accounting and word processing and for CAD. My business was owning a metal fabricating shop where I designed and built special industrial equipment, primarily material handling equipment. Changing to this model engine building was a big change. Previously +/- 1/8" was precision for a lot of stuff.

 

[Richard Hed]

Yes. I am that old (82). I started out with a Kaypro computer with CP/M operating system sometime in the 70"s with a single 5" floppy where you loaded the program into memory and then removed it and entered the data on the next 5" disk. Going to a PC where you entered DOS commands instead of a graphic interface was a big improvement. Computer use was never the main part of my business but I used a computer for accounting and word processing and for CAD. My business was owning a metal fabricating shop where I designed and built special industrial equipment, primarily material handling equipment. Changing to this model engine building was a big change. Previously +/- 1/8" was precision for a lot of stuff.

LOL, yes, the Kaypro. I knew someone who had one and I drewled all over myself wanting one of those. I evcentually got my first computer in 1977--a Radio Shack TRS-80. Slowly bought th3e parts that made a real computer with a zinging 4MB clock, two floppy drives (each 500$) and a printer (1700$) and what a clunker it was! In the end, it cost a total of 5000$ in 1977 dollars. I estimate that to be somewhere around 35000+ $ in our money today. I mean you could buy a loaf of bread for 25c back then. I would be reading magazines that advertised a COLOR computer for 13000$ which I also drewled over. It had 4 colorsw. In '88, I got my second computer which was an Amiga--for the $ it was the berst computer ever made. Had they stayed in business, I thimpfks it would be the best today if they had kept up with all the innovations. I still have that Amiga. There are Amiga clubs today, did you know that?

 

[Daryl_bee]

That's pretty much the way I do it. I'll model a single tooth (It doesn't have to be fancy, but the geometry is pretty simple as are the tooth calculations.) & as Richard says, make a circular pattern of that tooth profile.

snip...

John

Dude, you have Pro-E and you draw gears?! Use these (they're Wildfire 4). Make a copy or back-up for a new gear (I save these masters in my "Bolt_Bucket" folder under "Gears"). Open and go into parameters. Enter the DP (Diametral Pitch), N Number of teeth, PRESSANGLE (pressure angle) & CLEARANCE then "regenerate". Voila, your raw gear. After that you can play with the width, cut spoke holes etc.

 

[PeteH]

8 inch floppies rule! Hard sector too, none of that new fangled stuff from people who don't appreciate AO horn rimmed glasses and a good pocket protector! Got to boot that 360 or VAX from something when you IPL! I remember Generic Cadd too, kept me using vellum and t squares for a few more years it was so klunky

8 inch single sided floppies, 5mb HDD shared between 6 terminals, tectonix graphic screen - monochrome and À0 digitiser all running in-house drafting package programmed in basic!

No editting function 'on screen' could only delete a line and add new. . This was mid 70's

 

[TimTaylor]

8 inch single sided floppies, 5mb HDD shared between 6 terminals, tectonix graphic screen - monochrome and À0 digitiser all running in-house drafting package programmed in basic!

No editting function 'on screen' could only delete a line and add new. . This was mid 70's

I still have a PDP11/130 that has an 8 inch floppy - also have a DG Nova 4