How to make a ledge

[ianhughes7UFVF]

Hi

I am trying to make a 3d printed frame. The Top Plate is going to be 10mm thick but I want to make it in segements.

This is my first idea:

8 segments, but I needed to make ledges on each side of the individual sections one on the bottom and one on the top of each to be able to join them.

So the sketch I adjusted to look like the last picture, so it will give me a 10mm cut out on one side and a 10mm extension on the top of the other side.

I extrude the section 10mm but carn't seem to make a ledge on the bottom side properly. The cutout needs to be 5mm up.

Hopefully you can understand what I am asking. I have attached the design for you to look at.

Its basically so I can glue each section together with some retention.

Kind Regards

Ian

[ianhughes7UFVF]

Hi

Once again thank you for your screencast. I would never have thought of the project tool in this regards. I have only used it once before but can see that it will work for this process.

I will have the opportunity to apply your explanations tonight when I get home and have a go at this.

Only one thing though is the hole that is created whilst centered according to the shape we have doesn't come out centered between the inner and outer diameter. I would like to get it directly in between the the two which would mean it needs to move further to the outer edge. Would this be like adding a mid diameter circle to the sketch to be able to find a center point.

I hope you understand what I am after.

Kind Regards

Ian

[lichtzeichenanlage]

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@TrippyLightingwrote:

It is not surprise that this does not work for you. Your sketch is in one word unusable.

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I love our German mentality 😉 Einnorden (IMHO to orient doesn't even come close to the meaning) and excuses.

[TheCADWhisperer]

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@ianhughes7UFVFwrote:

.... I want to get away from 2d cad ...

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You will never master 3D Modeling without first mastering 2D CAD.

Your sketches are either underconstrained/missing dimensions or using dimensions that are not measureable.

Nearly all 3D CAD is generated from 2D CAD foundation.  Build that foundation rock-solid, robust and predictable to edits.

[ianhughes7UFVF]

Hi

I realize that creating 2d sketches in Fusion 360 is the start of creating work there and then developing the 3d from that. This is an old post that I dug up as I am revisting the project. I had used draftsight 2d cad for most of my work and then imported dxfs into fusion and then worked from there.

The context of my comment was that I had relied on that method too much. Now I want to stay inside fusion for my projects.

Trippy-Lighting has been a source of great direction in my learning curve of using fusion. I still make alot of fundamental mistakes but I also do alot of things correctly, so I am more than happy to be guided by his experience.

My original drawing was a mess I realize and I hope with aid from here that I will iron out any mistakes.

Kind Regards

Ian

[TheCADWhisperer]

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@ianhughes7UFVFwrote:

....I hope with aid from here that I will iron out any mistakes. 

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Can you File>Export and then Attach your latest version here?

Then someone can show you how to parametrically place those holes according to your design intent.

(I saw other issues relative to Design for Manufacturability - whether conventional or additive that should be addressed at the same time.)  Trippy didn't get that far along (DfM) with you yet.

The examples in Post 2 and 14 are not manufacturable/assemblyable (are those words?).

[ianhughes7UFVF]

Hi

Yep, I will be working on the design tonight hopefully and will be able to post tomorrow.

Sorry, a slow student 🙂

Kind Regards

Ian

[chrisplyler · Accepted solution]

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@ianhughes7UFVFwrote:
Only one thing though is the hole that is created whilst centered according to the shape we have doesn't come out centered between the inner and outer diameter. I would like to get it directly in between the the two which would mean it needs to move further to the outer edge. Would this be like adding a mid diameter circle to the sketch to be able to find a center point.

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Then do something like I show below. I'm beginning to suspect that you ought spend SOME of your time learning about the Fusion tools and SOME of your time just learning how to think geometry.

[ianhughes7UFVF]

Hi

That's exactly what I need.

I am itching to get onto doing this. I have been tied down with work and running the kids around in the evenings and had no spare time to work on fusion.

So hopefully tonight, and I can upload the piece and see if I got it right.

I have used basic tools like the extrude, align, mirror, import dxfs, create alot, but not the project tool alot so this will be a good lesson in things. I hope to improve with time.

Thanks again.

Kind Regards

Ian

[ianhughes7UFVF]

Hi

So using both screencasts, I was able to create the Top Plate to the dimensions I am after.

I have attached the file for you to check out.

Once I used the project tool I found it easy to create the holes, although I did this by stepping back the timeline so it was applied to all eight parts.

The next thing is I want to make component one and component five have a groove 5mm deep on the underside to allow a plate to slot vertically into it. That is my next step but I will have a go and let you know my progress.

Thanks for the help you have given.

Kind Regards

Ian

[TheCADWhisperer]

Sketch1 is not fully defined (the lines are blue rather than black).

Edit Sketch1 and try click and drag of endpoints.  What do you observe?

What instrument will you use to measure the 199.743 mm dimension.

Once you have fixed these issues - I can suggest some edits to improve Design for Manufacturability/Assembly (either subtractive or additive).

[ianhughes7UFVF]

Hi

The 199.743 is the inside radius of the of disk I am making. The outside diameter is going to be 459.486 allowing a 30mm width to the disk.

This is going to become a 3d printed R2D2 Frame project I want to create.

I have done alot of frame designs and this is something I want to try.

For example, this is a frame I want to make in aluminium at somestage:

So likewise here, rather simplified I intend to have a simular 3 or 4 disks and side supports. This frame was done in fusion but all the components were inserted dxfs.

So when I edited sketch one, and selected the drag points they created an edit box that would select a section, either a half section of the ledge or if to the right, the whole right of the plate.

I am not sure I understand what I have to fix as it appears correct. This is obviously my ignorance and inexperience speaking.

Kind Regards

Ian

[TheCADWhisperer]

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@ianhughes7UFVFwrote:

The 199.743 is the inside radius of the of disk I am making. The outside diameter is going to be 459.486

I am not sure I understand what I have to fix as it appears correct. This is obviously my ignorance and inexperience speaking.

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You would have great difficulty measuring out to 3 decimal places.

You did not answer my question.  What measuring instrument are you going to use to measure this dimension?

You will certainly not 3D print to 3 decimal places.

I recommend always using real world dimensions. (including consideration of real world manufacturing tolerances)

Back in a minute with video of constraint issues.  Stay tuned!

[TheCADWhisperer · Accepted solution]

Turn on your sound.

[ianhughes7UFVF]

Hi

I see what you are getting at and for the first time I understand what it means to constrain something. I have been told and told hundreds of times that my work is unconstrained and now I see what you are getting at. I can go back and make that correction.

The 199.743 has been about my conversion from inches to metric. I am in Australia and with alot of R2D2 Prop building nearly all the measurements are in inches. I have had to convert everything to metric and when adding measurements together  I have leaned towards as many decimal places during the addition or subtraction but rounded the amounts up to one or two decimal places as a final figure. In regards to that amount it would be no hindrance to just make it 200mm, which is probably what I would have done in the end.

Would I need to redraw the design or could I adjust that length within the design?

Kind Regards

Ian

[TheCADWhisperer · Accepted solution]

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@ianhughes7UFVFwrote:
....Would I need to redraw the design or could I adjust that length within the design?

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No, no, no.

That is the beauty of fully defined geometry - it is so easy and predictable to make edits.

Simply double click on the dimension and change it - the dimensions drive the geometry.

[chrisplyler]

@TheCADWhisperer

It certainly doesn't HURT anything to call out that dimension to three decimal places. His 3D printer likely can't hold to a 1.000" accuracy either, so using a nice round number versus something that LOOKS complex to our minds doesn't really make a difference. A computer doesn't distinguish between one or the other.

[TheCADWhisperer]

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@chrisplylerwrote: 

It certainly doesn't HURT anything to call out that dimension to three decimal places. . 

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I would argue that it most certainly does HURT, but I give up arguing.  Continue on with your beliefs.

I come from a background of 8 yrs out on the shop floor.

Nothing drives me more crazy than designers who do not consider real-world Design for Manufacturability from the foundation of everything they do.  They argue... ...well, as I said, I give up.  I can annihilate their arguments, but I have to go mow the grass.

[ianhughes7UFVF]

Hi

Any way, I made those adjustments and its really nice to be able to make that adjustment in measurements with the program.

I am also now going to have fun trying to start adding constraints to my work.

The next hurdle is adding grooves in to a piece.

I want to add a slot into those plates one and five:

It needs to be 20mm in from the Outer edge and 5mm deep. I haven't worked out the length yet, but would I assume this would be editing a specific component and perhaps creating a rectangular sketch and then negatively extruding it.

By the way, don't mow the lawn yet, I am listening to your advice and respect your opinion.

Kind Regards

Ian

[chrisplyler]

@TheCADWhispererI think I know your arguments. It's easy for a guy laying out sheet metal with a scribe to mark 1.000" but it's NOT easy for him to mark 1.0367917548", right?

That's absolutely valid.

My point was that it doesn't hurt was only intended to be applicable to computers. Like if the part will be 3D printed or cut on a CNC laser or waterjet. You just send the file to the machine, and the machine gets it as close as it can within its mechanical tolerances, regardless of whether a value is rounded off nicely or not.

[ianhughes7UFVF]

Hi

So now I want to add a side plate that connects into the top disk.

Here is the side plate that made using fusion only. I hope it is correct.

I have add the file which I have created in a separate design, which I will insert into the top plate one.

I just realized I forgot to create a component first and then build it.

Let me know what you think.

Kind Regards

Ian