3D pipe runs in CAD

[IanTParticipant @iant]

Posted by SillyOldDuffer on 01/05/2023 13:01:37:

"The problem is me. I've been using the 2D sketcher for months. The 3D sketcher is similar, and I've forgotten the differences, so it doesn't do what I'd expect (in 3 dimensions)."

Dave

"Isn't it just a matter of starting a line/curve in one view (say Front) and then continuing into Top and the Left view etc, until you have the shape you need, then finishing with a Sweep to make the solid?"

Martin.

Thought I'd better stop hi-jacking Nigel's Alibre notes…

Not tried this in Solid Edge before. Drew a (random) 3D line using simple vertical/horizontal controls (very easy in 3D Sketching) and was then left puzzled about fleshing this out into a pipe run…

I did it without too much of a struggle by using the 'line' as a template and extruding cylinders down each line, changing the reference planes as I went. I then went back and rotated 'ends' onto each pipe bend…

It gave me what seems to be a workable solution but I'm not sure it's how an expert would do it – I'm probably missing something simple?

Regards,

IanT

 

Edited By IanT on 01/05/2023 15:30:36

[IanTParticipant @iant]

First attempt at a pipe run in 3D

[Ady1Participant @ady1]

I would think that the more pricey 3D sketch software would be vastly superior for navigating around say a loco cab with micro piping

All your pipe turns are 90 degree 2D sketch moves, to go 3D I would have to start setting up fancy planes at fancy angles instead of the click-click of 3D working

[IanTParticipant @iant]

I was just trying to roughly emulate Martin's example in the Alibre thread Ady.

I did simple turns as it easy to do in SE but you can define alterate angles for them.

There are also several 'routing' and 'point-to-point' options in 3D Sketching that I imagine you can apply to an assembly as you suggest. So I think there is some 'automation' available for these things but I have first to learn to walk before I can run.

Regards,

 

IanT

Edited By IanT on 01/05/2023 15:56:44

[Ady1Participant @ady1]

Sorry, didn't realise you're just practicing

I've realised the limitation of Atom is proper 3D drawing which the more pricey software allows

3D drawing may also unleash our mojo where things like furniture design and architecture are concerned

[Anonymous]

I'd use a sweep function with a circle swept along a 3D path, as required. Mechanical CAD packages are not great for pipework. There are add-ons and standalone applications specifically for pipework, mainly aimed at the professional user.

In a similar way electronics CAD packages are not good at specifying wiring harnesses. Again there are add-on or standalone applications which ease the specifying of wiring harnesses.

Andrew

[JasonBModerator @jasonb]

Old video of it being done in Alibre

[Ady1Participant @ady1]

Wow

and that interface is a whole new universe

[Martin ConnellyParticipant @martinconnelly55370]

I used to get pipe data as a coordinate table on a drawing, use the coordinates to put the shape into 3D CAD, fillet the bends to the correct radius then sweep a circle along each line segment. I was then able to test if it could be manufactured as drawn by putting into a 3D model of the CNC pipe bender's head. and checking any dodgy bends that looked like they would cause the part to clash with the machine.

Martin C

[SillyOldDufferModerator @sillyoldduffer]

What I'm doing is a little more than a pipe run. I'm building a clock, where the pendulum swings in a vacuum. The clock base looks like this, scale, the block is140x240x48mm.

I have a vacuum pump which will connect to a bunch of 8mm plumbing attached to the block:

• Brass hose connector
• Open/Close valve
• 8mm T
• Vacuum gauge
• Screw fitting that penetrates through the block into the vacuum chamber
• 8mm copper pipe between above
• Fixings

Not much space inside the block, which also contains a microcontroller:

Needs planning, the hose and valve have to be firmly supported, the gauge visible, and the pipework routed into the vacuum chamber without getting in the way of anything else. Ideally the penetration point won't be too near the bob inside the clock because pumping out will disturb it.

So I'm modelling the parts to see how they might be attached to the model clock assembly. I did the valve without bother, just has to be the right size and shape:

I may use up to three elbows, and it was modelling one that gave me grief yesterday:

The pipe is made by sweeping a circle along a line representing the elbow bend, and I'd forgotten how to change plane in the 3D sketcher. It's easy when you know how! The sweep creates a solid rod, which I hollow out with the 'Thin Wall' tool. This particular tool finishes with a right-click, which I'd forgotten, and also how to tell it to do a pipe open at both ends. It produces a closed tube by default.

Next I have to model the T coupler, hose fitting and gauge. Once they're available, the parts can be added to the clock assembly and interconnected with a pipe run created by the 3D sketcher.

The 8mm pipe can be modelled as a solid rod, but the other components need realistic 8mm holes because the pipe plugs into them.

I could work the plumbing out by positioning real parts around the real clock, but I've found CAD modelling is so close to real machining that it's worth modelling to be sure holes, pipes and whatnot won't accidentally interfere. For example, I can make holes and run pipes in the model with the model microcontroller fitted in the base, seeing instantly if any of them are bad news. Not a good idea to machine actual metal with delicate electronics or anything else attached!

Dave

[blowlampParticipant @blowlamp]

There are no special tools to do this in MoI, just draw the line and Sweep the profile.

Notice how there's no need to position the profile on the rail – as long as the profile is outside the bounding box of the rail, then MoI will assume you want it rotated & centred along the rail. If you position the profile yourself, then it will be swept accordingly.

By adding Points to the curve, you can see that it's possible to create more complex shapes – the generated solid can be updated by moving the Points, or even by updating the diameter of the profile.

 

Martin.

 

Edited By blowlamp on 01/05/2023 17:32:37

[blowlampParticipant @blowlamp]

Posted by SillyOldDuffer on 01/05/2023 17:15:11:

I could work the plumbing out by positioning real parts around the real clock, but I've found CAD modelling is so close to real machining that it's worth modelling to be sure holes, pipes and whatnot won't accidentally interfere. For example, I can make holes and run pipes in the model with the model microcontroller fitted in the base, seeing instantly if any of them are bad news. Not a good idea to machine actual metal with delicate electronics or anything else attached!

Dave

 

 

 

I think I'd be using Kunifer brake pipe (or similar), to keep it more compact, it's easier to bend too.

 

Martin.

Edited By blowlamp on 01/05/2023 17:30:17

[JellyParticipant @jelly]

Posted by Andrew Johnston on 01/05/2023 16:15:52:

I'd use a sweep function with a circle swept along a 3D path, as required. Mechanical CAD packages are not great for pipework. There are add-ons and standalone applications specifically for pipework, mainly aimed at the professional user.

In a similar way electronics CAD packages are not good at specifying wiring harnesses. Again there are add-on or standalone applications which ease the specifying of wiring harnesses.

Andrew

Indeed.

My experience is that if you don't have access to Plant3D (AutoCAD)/ Modular Plant Design (Solid Edge)/ MEP (Revit) or one of the many add-in or standalone piping design programmes, it is simpler and easier to ignore 3D modelling of the pipe systems and just do your piping iso's in 2D cad or by hand.

This is based on designing large runs of DN50-DN200 (2"-8&quot piping comprising multiple spools with complex geometry to fit round various constraints like existing pipework and supports.

Given the Piping Iso is the ultimate product of a piping design process which communicates design intent to the fabricator, 3D models of the elements are non-essential.

[SillyOldDufferModerator @sillyoldduffer]

Posted by blowlamp on 01/05/2023 17:29:06:

Posted by SillyOldDuffer on 01/05/2023 17:15:11:…

…

I think I'd be using Kunifer brake pipe (or similar), to keep it more compact, it's easier to bend too.

…

That's where I started, but I couldn't find anyone selling all the bits needed to complete the system. Maybe I was unlucky, but 8mm was the smallest size in which I could find all the bits off-the-shelf. It's not because I didn't think of brake pipe. If anyone provides a link to a seller who could have supplied the needful, I shall have a tantrum!

Dave

[JasonBModerator @jasonb]

Dave, can't you download files for those plumbing fittings off the net to save having to model them

[David JuppParticipant @davidjupp51506]

You might find a wider variety of valves/fittings/ tubing/connectors in inch sizes – a lot of instrumentation tubing is fractional inch sized based on tube OD.

[SillyOldDufferModerator @sillyoldduffer]

Posted by JasonB on 01/05/2023 18:17:42:

Dave, can't you download files for those plumbing fittings off the net to save having to model them

No excuses – I didn't think of it!

In similar vein, Blowlamp and DavidJ's alternatives to 8mm make me wish I'd asked for vacuum system advice before plunging in at the deep end. Not doing so has made life difficult because I have almost no experience in pipework beyond domestic water, and could have got expert help.

Dave

[JasonBModerator @jasonb]

I'd have gone with push fit pneumatic myself, 4, 6, 8 and 10mm easily available and if you plumb it up wrong the first time you can pull it apart and start again. PVC pipe is flexible so you can run it as you wish

[David JuppParticipant @davidjupp51506]

Most small bore valves/fittings are designed primarily to keep pressure in – they may not necessarily perform as well if required to keep pressure out (though many will probably be OK). You may want to check for if components are suitable for vacuum duty.

[SillyOldDufferModerator @sillyoldduffer]

Posted by David Jupp on 02/05/2023 11:11:53:

Most small bore valves/fittings are designed primarily to keep pressure in – they may not necessarily perform as well if required to keep pressure out (though many will probably be OK). You may want to check for if components are suitable for vacuum duty.

I'm worried about that! It's why I avoided push-fit. Soldered fittings should be fine, and I guess compression joint olives will be OK too. Not sure about the gas tap, but I expect it's a ball-valve. The vacuum gauge and BSP adaptor should be OK. The danger points appear to be the fitting that penetrates the base and the seal built into the top of the pipe, which is the wrong way round for a vacuum but I can glue the cap as well.

Biggest concern is the o-ring or sealant at the bottom of the 4" pipe where it sits in a groove cut in the base. It relies on the weight of the pipe and air pressure to maintain the seal. If it leaks, Plan B is to glue a 3D printed flange to the pipe allowing it to be screwed down to the base.

I don't know yet how good the vacuum will be even if there are no leaks. The pump is an elderly old banger like me.

Assuming I get to pumping it out – still struggling to get the electronics working reliably.

Dave

[JasonBModerator @jasonb]

My vacuum press uses the push fit connections and it's a very popular model so must work OK

[Martin ConnellyParticipant @martinconnelly55370]

Don't forget that the maximum pressure differential between a vacuum and atmospheric pressure is less than 15psi and slightly more than 1 bar. Compare this to compressed air at maybe 75psi, steam at 200psi or hydraulics at 3000psi and you should appreciate that holding a vacuum is not an arduous task for most fittings.

Martin C

[John McNamaraParticipant @johnmcnamara74883]

If extruding or sweeping a line Instead of abrupt 90 degree changes in the line try filleting the bend first, then extruding the pipe form over that. In real life pipework there is always a radius, the canter point is normally outside the pipe itself in free space. This will give a more natural form of bend.

[JellyParticipant @jelly]

Posted by Martin Connelly on 02/05/2023 12:44:44:

Don't forget that the maximum pressure differential between a vacuum and atmospheric pressure is less than 15psi and slightly more than 1 bar. Compare this to compressed air at maybe 75psi, steam at 200psi or hydraulics at 3000psi and you should appreciate that holding a vacuum is not an arduous task for most fittings.

Martin C

Logically yes, practically it depends on how much vacuum you actually need to maintain and for how long.

Holding ultra-high or absolute vacuum requires a near perfect/actually perfect seal at a molecular level, which is more challenging than maintaining "good enough" sealing performance in the containment of steam/oil/compressed gasses.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Jelly on 02/05/2023 13:05:52:

Posted by Martin Connelly on 02/05/2023 12:44:44:

Don't forget that the maximum pressure differential between a vacuum and atmospheric pressure is less than 15psi and slightly more than 1 bar. Compare this to compressed air at maybe 75psi, steam at 200psi or hydraulics at 3000psi and you should appreciate that holding a vacuum is not an arduous task for most fittings.

Martin C

Logically yes, practically it depends on how much vacuum you actually need to maintain and for how long.

Holding ultra-high or absolute vacuum requires a near perfect/actually perfect seal at a molecular level, which is more challenging than maintaining "good enough" sealing performance in the containment of steam/oil/compressed gasses.

Jelly states the problem well – even a tiny leak will destroy a vacuum, my container is only 2.3 litres of nothing, and an Oxygen molecule will get through a gap of about 1 billionth of a millimetre.

The vacuum is part of a pendulum clock, from which I hope to get high-performance. Pendulum accuracy is affected by air churning as the bob swings, and by changing air-pressure altering its buoyancy. Humidity can cause trouble too. So, it's desirable to pump out as much air as possible and to keep it out for several years.

Back to pipe routing, after much thought this arrangement is possible, so simple there's no need to route the pipe:

Only issue is the need for a 6mm diameter hole to be drilled 100mm  deep into the block. Straight, because wandering just a few millimetres left breaks out. Don't like it.

Dave

 

Edited By SillyOldDuffer on 02/05/2023 18:10:35

[Author]

Posts