Sweep of a solid

[mncad]

Is it possible to sweep a solid shape along a path? I have to recreate a part that was machined using 3 axis moves. I would like to make a solid of the cutter that was used then sweep it along a 3d sketch path. Can this be done?

Thanks,
mncad

 

[SBaugh]

You can sweep a sketch profile along a 3d sketch path, but not a solid feature. If you want to do that you need to look at animator. Animator will only simulate the cutter moving around the already made path.

See help on sweeps to understand how to make a sketch profile and path.

Regards,

Scott Baugh, CSWP
3DVision Technologies

http://www.3dvisiontech.com

http://www.scottjbaugh.com

faq731-376
When in doubt, always check the help

 

[TheTick]

Can you get the model from the CAM data imported into our file?

All this machinery making modern music can still be open-hearted.

 

[Andy330hp]

I'm not sure if this where you were going, but I think it would make a lot of sense if one of the 3D cad programs really did force you to use "tools" to make features. For instance, when you want a groove, you would still sketch a path but instead of using a sketched profile you would associate with that sketch "1/2" ball end mill" and BLAM it cuts the groove just like it would when the part is actually made. Is there any CAD program out there that operates like this? I'm sure there would be problems, I haven't given it too much though, but it seems like it would have huge advantages:
1. Keep designers from designing impossible parts
2. Streamline the transistion to CNC, since you'd have basically already written the G-Code, it would just have to be translated
3. (I think) you would end up with drawings dimensioned in a way the QC could more easily inspect

You would still need all the other features for doing casting design since their features are not limited to those that are easily machinable. But, what you could even do is differentiate between cast models (sldcas?) and machine models (sldmac), and limit the tools available to the machine models. OORR, still have the same features available even in the machine models, and have the CAD program automatically assign a tool and path. For instance, you do what bascically amounts to a facing operation by drawing a rectangular sketch and extrude cut, and CAD assigns an endmill and generates the toolpath. Then, these could be edited if desired.

Am I making any sense?

 

[mncad]

Andy330hp,

Sounds like you need to start wrinting code and marketing. I know I would be the first in line to buy it. I know when our VAR was here selling us on Solidworks they said, "if you can machine it we can model it". I know of alot of things I can do with a cnc 4 or 5 axis machine that are pretty much impossible to model in SW without the capability of sweeping (cut) with another solid. Multi bodies doesn't always get it done because it won't let you generate a body that comes back on itself, something that almost all toolpaths on a milling machine do. Guess it is time for an enhancement request.

mncad

 

[brengine]

Andy330hp,
I've been trying off and on for a few months to figure out a way to sweep a solid too. No luck. I do the 2D sketch profile for moves parallel to one of the main 3 planes, but a move that isn't parallel to one of those planes takes a lot of *manual* work.

I WOULD like this as an option, and yes there are some really funky possibilities with 4 and 5 axis machines, but as for all Cut operations behaving this way in a Solid Modeller, FORGET IT. For one, designers aren't necessarily machinists, or would image it being made the exact same way the machine shop would choose to make it. And for another, have you ever seen a ball nose end mill cut a 3D contoured surface? There are literally thousands of moves. I've seen 50MB text files generated by our CAM for the CNC mill, and that's for a puny little 8" tall shampoo bottle mold...imagine a 55 gallon trashcan or car body half (Chrysler was working on something a couple years ago). Give me at least a profile/guide curve/sweep over that every time, or argueably even better a good surface modeller instead.

As for desgns, besides square inside corners (which could be done with a plunge EDM, but a a considerable cost), there's not alot out there that can't be machined. Granted, I've seen (and done) some impossible stuff here and there (or possible, but very costly). And I do agree that the designer should keep in mind how they think it could be made, and knowing some of the basic machining strategies would be a definite help. But designing and building can be 2 completely different animals.

Just my $0.02,
Ken

 

[Rocko]

What i have had to do in the past to get what i want is use multibody and create essentially a cutting/die solid to cut into a base shape to get the final result lik what you want.

 

[Arlin]

Well said, Ken.

While a designer should be aware of manufacturing limitations and design accordingly, the designer SHOULD NOT tie his design to a particular manufacturing process.

IMO, the designer only needs to document design intent. The design should allow manufacturing the flexibility to choose what method would best produce the specified design, which may change over time.

One day, the best mfg process may be to machine the part, later it may become advantageous to cast the part in a finished state. In the distant future, perhaps a Star Trek style Replicator could be used. In each case, a good design will allow these changes to the mfg process with little or no revision necessary.

 

[dgiy]

We could all use a good replicator.
Transported wouldn't be bad either.

Let me get crackin' on them. I'll let you know what I come up with.

DG

 

[JNR]

For a workaround, how about doing a zero surface offset and sweeping the surface?

'Tis true there are some differences between the requirements of pure CAD and NC, etc. It is usually a good thing to prevent sweeps of solid bodies in pure CAD applications because the logical results can be illogical and mathematically unsound. Remember that they have to look at the general case, not special nicely symetrical cases like tool points. However I agree that they should think about allowing the user to consciuosly attempt a solid sweep, perhaps with appropriate warnings iy the user thinks it is appropriate.

3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......

 

[carterskemp]

in response to your "replicators"...

many of you have probably heard of such things, but...

SLA(stereo lithography),are basically replicators. 3D "printing" in wax, resin, metal and plaster. fantastic for display, presentation or casting.

http://www.stereolithography.com

is pretty interesting.

carter

 

[JNR]

We use "replicators" a lot. The basic concept is called "Rapid Prototyping" (which strictly includes some NC and other methods, but....) Many people refer to all types as "SLA" ,but that is a misnomer much as "Xerox" is often used to refer to any photcopying.

All the methods create a part directly from 3D CAD data. All "replicator" methods slice the model into many very thin cross-section layers and build them sequentially on top of eachtother.

SLA is one process (Stereo Lithography) and was the first. it basically fuses a polymer soup with a laser.

SLS (Selective Laser Syntering) fuses layers of powder.

FDM (Fused Deposition Modelling) and 3D printing actually print layers of material like an inkjet printer kind of thing.

The Z Corp. machine fuses layers of powder by printing a resin onto them (poor surface finish and strength, but you can have colors throughout the model - real interesting if you use the results of an FEA model!!)

There are machines which have two material types, one being soluble. This gets around having to use support structure under hollow sections in some methods (and having to remove it afterwards). This is not an issue with the powder machines - you just shake the loose powder out!

Surface finish is not perfect, and varies depending on the machine and the layer thickness - also the detail geometry, like radii.

There is one SMALL but highly accurate surface fideilty machine (great for jewelery!).

There is also a LARGE machine that laser cuts sheets of butcher paper and heat/pressure fuses them. The voids are automatically "diced" and shaken out afterwards. Apparently some bright spark found out that butcher paper is incredibly consistent in thicknes and the shiny resin surface fuses into a solid "wood" block nicely.

Some new materials are flexible, some are very strong - you can now supposedly even get "glass clear". Waxes can go straight to investment casting (great - we do this a lot). One process used for this prior to the wax machines (Hollocast) made a honeycomb like structure instead of solid in resin (SLA) then burned this out of the mold. It had its problems and we can find a foundry who will use it today now that wax is available. One company uses the Z Corp. machine to directly create he investment cast mold! Good price and VERY fast turn, but not can have a lot of distortion and surface finish is really crappy. You can now even create powdered metal parts and fuse them in a furnace.

It's cool stuff. Not cheap but can often be very cost effective. It is really neat to see your design in 3D without any drawings, etc. for the first time.

Rumor has it that one photocopier manufacturer actually made several hundred production parts due to last minute design change while a long-lead mold tool was being. built.

3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......

 

[Arlin]

Yes, there was a reason I said STAR TREK STYLE replicators.

Current "replicators" have many limitations such as time, cost, and material. However, a STAR TREK STYLE replicator can create almost ANYTHING out of ANY material almost INSTANTANEOUSLY. Just give it the geometry and composition and it turns energy (a lot of it) into matter.

Until then, these modern day replicators (Rapid Prototyping)are indeed very cool.

 

[TheTick]

There is still no good way to "replicate" a stamping.

 

[JNR]

Interesting, why do you say that, Tick. Is it just the modelling issues in true material stretching or something else (or my idea of what you mean by stamping is different from yours).

BTW: I hope and trust that we never do actually achieve Star Trek style replicators. I think that the entire ecconomy and ecology of the world, perhaps the universe, would fall appart. The more I think about the possible consequences the less I like it.

3/4 of all the Spam produced goes to Hawaii - shame that's not true of SPAM also.......

 

[TheTick]

I'm in the stamping business nowadays. SLS and its kin just do not cut it when it comes to matching the physical properties of stamped steel. Stamping prototypers still make full forming tools and hit parts.

Fortunately, there are some great stamping proto shops out there. I highly recommend Quasar Industries.