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Is anyone up to a challenge?

HaroldL

Alibre Super User
Here's a modeling challenge for anyone inclined to take it up. Model part 49 on the attached drawing. I found an issue with the size or location of the tab pairs that are patterned around the part. I'd be interested to see how you resolve the issue.

Point of reference, part 3 needs to fit on the top of 40 as a cover.
Carreras soto 14_9.png

For more context here is an assembly drawing for the completed model:
Carreras soto 14_6.png
 

Ken226

Alibre Super User
That was pretty challenging. There were a few dimensions that I couldnt find, but managed to get pretty close by adding/subtracting other dimensions and eyeballing the drawing.

The transverse hole in the bottom half calls for a 3mm deep counterbore, which doesn't look right as it nearly goes all the way through. The drawing pic looks like its probably supposed to be 2mm deep, so I made it 2mm deep. :)

It didn't call for any fillets or chamfers bet there appeared to be a couple pictured, so I put them in anyway. The pattern issue, I think you'll see how I dealt with it immediately from the pic.

Otherwise:

1659907571635.png


1659908136371.png
 

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  • Harold's Challenge.AD_PRT
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Last edited:

HaroldL

Alibre Super User
Geez Ken, that was fast. Finding the right dimensions is a constant battle with a lot of the drawings in the Carreras collection. I suspect that some of them are left for the drafter student to figure out on their own. I recall seeing that in Tech College a life time ago when I tool CAD Design Drafting. The instructor would point out that some of the dimensions on various problems were either missing or incorrect and we had to use our best judgement to figure them out.

The one issue I have on this part model is trying to interpret where the tabs intersect with the rim of the body. In both views it appears there is some distance between where the outer side of the tab intersects the top of the rim and the ID of the rim. Using the given dimensions I don't see how that is possible.
The counter bore dimension line you mentioned doesn't even align with the c-bore bottom so your solution is likely correct, And the screw that in installed in that hole is item 51 on page 13.

Here is a link the PDF book that the drawings are taken from, I should have attached this before, it contains the remaining parts for the model as well as other model drawings.


And here is a link to the web site that has more of the work of T Carreras Soto:

 

Ken226

Alibre Super User
Geez Ken, that was fast. Finding the right dimensions is a constant battle with a lot of the drawings in the Carreras collection. I suspect that some of them are left for the drafter student to figure out on their own. I recall seeing that in Tech College a life time ago when I tool CAD Design Drafting. The instructor would point out that some of the dimensions on various problems were either missing or incorrect and we had to use our best judgement to figure them out.

The one issue I have on this part model is trying to interpret where the tabs intersect with the rim of the body. In both views it appears there is some distance between where the outer side of the tab intersects the top of the rim and the ID of the rim. Using the given dimensions I don't see how that is possible.
The counter bore dimension line you mentioned doesn't even align with the c-bore bottom so your solution is likely correct, And the screw that in installed in that hole is item 51 on page 13.

Here is a link the PDF book that the drawings are taken from, I should have attached this before, it contains the remaining parts for the model as well as other model drawings.


And here is a link to the web site that has more of the work of T Carreras Soto:



Yea, I scratched my head for a sec wondering about that intersection, when I started dimensioning my sketch reference figures. I decided to prioritize the numbers over the appearances.

The drawing also shows edge curves rather than intersects, but no fillet callouts in those locations. So I just ignored the pic and went by the numbers.

While modeling a part, I also try to visualize the paths an end mill or lathe tool will have to take to produce a feature, and sometimes that habit ends up directing my workflow.
The 4 slots were an example of that. Both views showed them with circular ends, which would mean a mill with a 4th axis, or an odd rotary table setup and some careful re-indicating. So I ended up sketching using a midplane cut, with fillets to round the ends.
 

Ken226

Alibre Super User
I had some more downtime today, so had a go at #3.

It had some dimension challenges as well. The location of the lower radius center was tough, and there were a couple dimensions on the top that didn't work. I adjusted them to minimize the amount of change yet still work.

1659974357685.png


But, they do seem to fit together.

1659974408428.png


In cast iron:

Pressure Regulator.5.jpg
 

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  • Part 3.AD_PRT
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HaroldL

Alibre Super User
Ken, I haven't downloaded your model yet but it looks like your seeing some of the same issues I ran into.
On part 49 I had the same issue with the tabs bumping into the rim. I used a revolve cut to remove the extended bits. I made the sketch align to the same angle as the rim outer face by using project to sketch.

tab to rim.png


For the slots in the bottom, the drawing showed them coming up into the flat face of the bowl. I couldn't get there with an extrude cut so I opted for a Boolean Subtract. And yes, I did add fillets around the tabs as shown on the drawing but guessed at their size and used 1.5 mm.

section 1.png


As a last step I tried to add Helical cuts for the M8 tapped holes in the tabs but the pattern fails because:
no pattern.png

So that is going to support.
 

Ken226

Alibre Super User
Ken, I haven't downloaded your model yet but it looks like your seeing some of the same issues I ran into.
On part 49 I had the same issue with the tabs bumping into the rim. I used a revolve cut to remove the extended bits. I made the sketch align to the same angle as the rim outer face by using project to sketch.

View attachment 36775


For the slots in the bottom, the drawing showed them coming up into the flat face of the bowl. I couldn't get there with an extrude cut so I opted for a Boolean Subtract. And yes, I did add fillets around the tabs as shown on the drawing but guessed at their size and used 1.5 mm.

View attachment 36776


As a last step I tried to add Helical cuts for the M8 tapped holes in the tabs but the pattern fails because:
View attachment 36777

So that is going to support.

I was able to model the thread with a helical cut. I used M8 x 1mm. To get it to work I had to set the pitch to a value very close to but less than 1mm. I used 0.99mm.

1659982531783.png
 

Attachments

  • Part 49.AD_PRT
    3.1 MB · Views: 1

GIOV

Alibre Super User
For the slots in the bottom, the drawing showed them coming up into the flat face of the bowl. I couldn't get there with an extrude cut so I opted for a Boolean Subtract. And yes, I did add fillets around the tabs as shown on the drawing but guessed at their size and used 1.5 mm.
It could be that the alternative is to use Fillet Edge Type Variable Radius.

Very good resource. I congratulate you. It may be that you make a series of tutorials based on the Timoteo Carreras collection.:)
 

Ken226

Alibre Super User
For the slots in the bottom, the drawing showed them coming up into the flat face of the bowl. I couldn't get there with an extrude cut so I opted for a Boolean Subtract. And yes, I did add fillets around the tabs as shown on the drawing but guessed at their size and used 1.5 mm.

I'm not certain what you mean here.

I modified the sketch i used for the midplane cut for the slots to come up a little higher. Is this what you meant? Up to the uppermost interior cylidnrical face?

1659985582113.png


I used a sketch on a default plane, with a midplane extrude cut, then four fillets.

As is my usual habit, I projected the interior geometry onto the active sketch as reference figures, so i can kind visualize the interior geometry as if it was a section view.

1659985745121.png


Then afterward, execute the midplane cut to the appropriate dual depth.

1659985843512.png

Then fillets, and a circular pattern of the cut and fillets.
 

Attachments

  • Part 49.AD_PRT
    3.1 MB · Views: 0

HaroldL

Alibre Super User
Ken, I actually started create the slots in a similar method as you did but the fillets at the top did not look "correct" so I opted for the Boolean method.


Very good resource. I congratulate you. It may be that you make a series of tutorials based on the Timoteo Carreras collection.:)
I though of doing that but I see that the folks at STUDYCADCAM have some already on YouTube. And I don't know the legalities of using these files for tutorials; are there copyrights that may be infringed on if I do create and publish some tutorials on YouTube. Sounds to me like a gray area 'cuz I've seen some SolidWorks tutorials by others that use the same files. :confused: :confused: :confused:
 

GIOV

Alibre Super User
though of doing that but I see that the folks at STUDYCADCAM have some already on YouTube. And I don't know the legalities of using these files for tutorials; are there copyrights that may be infringed on if I do create and publish some tutorials on YouTube. Sounds to me like a gray area 'cuz I've seen some SolidWorks tutorials by others that use the same files. :confused: :confused: :confused:
Harold,
If it is a practice training for free like mr. Constantin has, I think you are right for to do this in a nice Alibre collection Source and tutorials.
Here is an example in GrabCad with Inventor.
 
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