serrated tube ends---see image, who can tell me why?

[oldboot]

Following is a link to the image I made to show my problem.

http://graysony.nease.net/sw/serrate.jpg

I am doing a serrated tube end (with triangle shape teeth).

I have two ways to do that but the results are:
If I go method A, circulat pattern does not work at all.
If I go method B, circular pattern does work, but there must be space between copies

----But what I need is the patterned copied to be connect each other around the cirle.

Who knows why I fail? Could you play on you computer to see whether you get same result as I did?

 

[TheTick]

One more method to try:

•Copy one of the cylinder surfaces using "Insert --> surface --> offset" with an offset of zero (inner or outer)

•extend the surface edge beyond the solid cylinder body so there is enough extra to work with

•Put triangular cuts on offset surface using "Insert --> Surface --> Trim"

•Use the surface as a cutting tool by using "Insert --> Cut --> Thicken"



"When everyone is thinking alike, no one is thinking very much." --Eckhard Schwarz (1930--2004)

http://www.EsoxRepublic.com

 

[aamoroso]

I used to cut Hirth Coupling (V-Tooth) in my days as a mahcinist and one of the first projects I did in SolidWorks 99 was modling a Hirth Coupling on a Turbine Shaft. It has been a while but I believe what I did was draw the angle on the top surface as part of a revolve (the whole profile of the lathe work part). Then I drew a single triangle on the right plane (on the centerline of the part) and did an extrude cut outwards with draft on.

 

[aamoroso]

To further explain, I am guessing I did it that way because the top surface of you serrated tube is lathe work and the actual cuts in the angled surface are a secondary operation. I have found with strange parts like this it is sometimes advantageous to draw them as you would cut them in the shop.

 

[CorBlimeyLimey]

graysony

Neither of the methods you show will work because 15 circular patterned lofts will create joining edges of zero thickness when "in space" (ie. in the bore of your part). This is a limitation in SW, unless you create multibodies (ie. do not merge the result). A workaround might be to create your bore after the circular pattern.

In this case (in fact in most cases) however, I agree with with aamoroso, the best way to create your part is to simulate what actually happens in the machine shop. You do not need to create a sweep or loft, a simple V-cut is all that is required. The "overlapping" cuts will create the "tapered" shape of the serrations that you show. I have seen many great looking solid model parts, but, like Escher drawings, they cannot physically be made using standard machine shop practices.

from (the City of) Barrie, Ontario.

What happens if you get scared half to death twice?

 

[oldboot]

It is a plastic part by injection mold. It does exist on my desk.

I found a lady from Taiwan did an example using my intended method but it works, I don't know why she could pattern with zero space/thickness while my software says no.

Another way I found by someone else, he build 3D sketches --- 2 triangles on the inner and outer cylinder wall them 'loft' --- I knew nothing about 3D sketch at this moment. I will learn it soon.

An upside-down triangle-cut could make SIMILAR tri-angle teeth around. but as someone here already be aware that the top line of the triangle tooth is parrallel to the top surface --- The one I showed in image, the tooth top-line is not parallel to the top surface.

Anyway, I do very appreciate for your kindly help....I am not quite understand the words wrote by 'TheTick'---he is talking how to cut, but my prolem is on the circular pattern. I will try all the methods with your valuable suggestion.

Thanks you all again for your help!
Grayson

 

[ctopher]

I tried it by creating the tube and extrude it. Add axis thru center. Then create a sketch (one triangle) on the front plane thru the center. Then cut-through both directions (draft if needed). Then circular-pattern the cut feature around the axis. I hope this helps.

 

[aamoroso]

If its a plastic part a metal part that made it exists. This is called a Hirth Coupling, they are a fairly rare method of joining two shafts in high speed high precision applications. Check out -

http://www.amcprecision.com/v-tooth.htm

 

[CorBlimeyLimey]

If the peak & valley (top & bottom) of the serrations are "sharp" then one of them HAS to be angled to the tube end. If you want the top to be parallel, simply tilt the cutting plane to the desired angle or use Draft as aamoroso suggested.

I am guessing your Taiwanese lady cut the bore after doing the serrations, or used multibodies, or used some other software which allows zero thickness contacts.

from (the City of) Barrie, Ontario.

What happens if you get scared half to death twice?

 

[TheTick]

My previous post wasn't realy for the question of how to array. It was to illustrate a technique for making such "radially extruded" cuts.

As earlier posts state, I too believe you will have better luck cutting the teeth than adding them.

"When everyone is thinking alike, no one is thinking very much." --Eckhard Schwarz (1930--2004)

http://www.EsoxRepublic.com

 

[CorBlimeyLimey]

Completely off-topic but .... what's with the "Sponsored links" (the double underlined words) in peoples responses? Is this a new feature of the forums or is this some new kind of spam leaching into the threads?

from (the City of) Barrie, Ontario.

What happens if you get scared half to death twice?

 

[TheTick]

CorBlimeyLimey:

I really can't see what you are talking about from my computer. Can you name one specifically? Perhaps its a spamware infection on your computer.

 

[aamoroso]

I have seen similar things on my new Dell at home, I am guessing the double underlines you see are probably from a Dell user, there is a setting for it but I cannot remember how I turned mine off.

 

[SBaugh]

Off Topic --

CBL - Glad to see your back!! Haven't seen you in awhile! Where have you been hiding

To answer your question on the double green words

From: Dave
FYI -- we now run keyword advertising on the site. In the forums if key words match, you will see a double green underline.

Regards,

Scott Baugh, CSWP

http://www.3dvisiontech.com

http://www.scottjbaugh.com

If you are in the SW Forum Check out the FAQ section

To make the Best of Eng-Tips Forums FAQ731-376

 

[CorBlimeyLimey]

TheTick

It seems to be erratic or changing ... before I logged in your last post had one on "infection", and graysony's original post had one on "computer" in the last line. After logging in I only see one in your second post at "state".

I had the similar at home last night.

from (the City of) Barrie, Ontario.

What happens if you get scared half to death twice?

 

[CorBlimeyLimey]

Hi Scott, thanks for the welcome back.

Not hiding ... I have been doing some extra-curricular work for a friends company, which involved learning the ways of the "Dark Side" (Solid Edge 15). Very frustrating.

I have been following the threads all the time, just haven't allowed myself the time to particpate.

from (the City of) Barrie, Ontario.

What happens if you get scared half to death twice?