Which software for creating blueprints for a machinist?

Which software would I use to create prints for a machinist to use for him to then go on to use the file in his CAM software (like BobCAD-CAM)?

I want to have a design manufactured/machined in aluminum and the design is a drawing on paper right now.

Do you mean a printed on paper 2D drawing with dimensional annotations and other manufacturing information? This is what most machinists think when they hear "print."

Or a 3D CAD file that provides the machinist with a representation of the object that they can import into a CAM program? You mention importing into CAM, this usually means importing a 3D CAD file, as a "print" cannot be directly imported.

Or both? Depending on what exactly you are trying to get made, both may be needed or one of the above may be adequate. Machinists traditionally require a print with dimensions and tolerances called out, as the tolerance requirements determine the manufacturing process. Prints also usually communicate surface finishes, material requirements and any other characteristics that cannot be inferred from a basic 3D CAD file. But again, it's process dependent- for example, when I get parts waterjet cut from a certain supplier I never provide a print, just CAD files.

I've used Solidworks and Fusion360, both can be used to create 3D CAD models and a 2D print with printed dimensions etc based on that model. There are many other options as well.
Without more info on what kind of objects you are modeling, your budget, and/or what kind of info your manufacturer needs, it's hard to give a specific recommendation.

Just make a copy of the paper drawing for the machinist. If they know what they are doing they can handle the rest.

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carbonbl said:

Do you mean a printed on paper 2D drawing with dimensional annotations and other manufacturing information? This is what most machinists think when they hear "print."

Or a 3D CAD file that provides the machinist with a representation of the object that they can import into a CAM program? You mention importing into CAM, this usually means importing a 3D CAD file, as a "print" cannot be directly imported.

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Thanks for the clarification. I was imagining the former, the 2D drawing, with the manufacturing information. I worked as a CNC machine operator and always from those 2D prints. I always thought that the engineers provided the company with those drawings directly, and then the lead machinists would use BobCAD-CAM to write the CNC code.


Here's a more detailed description of the part.

A 13" aluminum cylinder 7 mm in diameter (so a rod I guess) with 15 degree bends 2 inches from each end (the bends in the same plane), and then 15 degree bends 0.75 inches from the ends so the ends are now back to parallel with the original length. Then the two ends rounded and faced flat on two opposite sides and then bored through. So it can be visualized as a long handle of sorts but the part is really a strut for a project I'm working on.

7075 AL
Clear Ano
+/- 0.005" on all tolerances

Budget isn't an issue. Free is nice, but I also have access to some slightly older versions of Solidworks and Fusion 360, and most other popular software through academia.

I imagine that the length can be turned from stock, but the bending I'm not so sure about. I think any mill can create the flat ends and bores. It needs to be functional first, and aesthetic second.

If it's something to be bent with limited machining then 2D is probably OK. Anything more complicated these days is best sent as both a CAD model and a drawing with key features highlighted.

And now for the backseat driving: Can you bend 7075? And if so this might be something you want to send to a specialist bending shop? I guess it's only 15 degrees. As for machining it first, is 7mm critical? Why not make it out of 5/16" nominal rod which is about 8mm. That will save a lot of work. Or if it could be square in profile just mill or waterjet it from bar. The choice of solid 7075 is a bit strange in that you are going for a high performance alloy for a strut, which suggests something aeronautical or similar, but if you wanted it to be really light you'd want to go with a tube, even a 4130 tube as it would be easier to prototype. Or CNC the two 2" long end pieces that jog back and glue them to a section of carbon fiber tube in the middle.

A proper modern shop will use a model, whether the customer provides it or they have to model it from the print. It's far more efficient if you provide an accurate model, modeled with every feature at the midpoint of the tolerance band, AND a complete, fully dimensioned and toleranced print. It saves them having to do it for you while guessing at what you want.

rcoope said:

If it's something to be bent with limited machining then 2D is probably OK. Anything more complicated these days is best sent as both a CAD model and a drawing with key features highlighted.

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Would Solidworks or Fusion 360 both be suitable then to produce both the model and the 2D drawing?

rcoope said:

And now for the backseat driving: Can you bend 7075? And if so this might be something you want to send to a specialist bending shop? I guess it's only 15 degrees. As for machining it first, is 7mm critical? Why not make it out of 5/16" nominal rod which is about 8mm. That will save a lot of work. Or if it could be square in profile just mill or waterjet it from bar. The choice of solid 7075 is a bit strange in that you are going for a high performance alloy for a strut, which suggests something aeronautical or similar, but if you wanted it to be really light you'd want to go with a tube, even a 4130 tube as it would be easier to prototype. Or CNC the two 2" long end pieces that jog back and glue them to a section of carbon fiber tube in the middle.

Click to expand...

7mm is important because of certain proportions I'm trying to achieve, and cylindrical in shape is a must for the same reason. As for 7075 what I need is a thin strut that can manage 100lb or so of force in various directions except directly by elongation, so mostly compression; I'm not sure if 6061 is suitable and I'm not familiar I don't think with 4130. I am open to it being a hollow rod as the strut needs to be as light as possible, but strength and longevity and repeated use is more important.

Bicycle chain rings are of 7075 I think mainly because of wear resistance. I think in the mid-1980s chain ring designers switched from steel to 7075 because of this as well as for a weight savings I believe. I only bring this up because I'm not planning on sending anything to space I think I just prefer to over-engineer something at this point.

Autocad V2.0 or upwards in brands or versions.
T'is not the software it is the guy using it.
Bob

Solidworks, Fusion 360 or OnShape would all be fine. I must assume that this is part of a larger project though so don't you have to have a lot more CAD drawings?

My rule for 7075, and this is in no way scientific, is that if you think you need it over 6061-T6 you are into a realm where you should have calculations to show this is the case. 6061 and 7075 have similar elastic modulii at about 10,000 ksi so stiffness will be the same, and even at a yield strength of 35,000psi a 7mm 6061 bar will yield at over 2000 lbs. So you could go lighter with tubing, but cracking might be an issue when you bend it. 2024 is also an option as its UTS is in between the other two. Various bike parts get machined from it like stems. 4130 is Chromoly steel and has a high Young's modulus albeit at 3x the density. But I bet you'll be able to do something clever with tubing there and get great stiffness if that's a consideration. Do give thought to relaxing your 7mm constraint to allow for 5/16" (7.9mm) though, Or even 3/8" (9.35mm) as then you can get .065" wall 2024 tubing which would yield at 2,850 lbs. I see on McMaster you can't get rod or tube in 7mm so you'd have to turn it down which is not totally trivial as the part is long and thin.

"Budget isn't an issue. Free is nice, but I also have access to some slightly older versions of Solidworks and Fusion 360, and most other popular software through academia."

-Small point that may/may not be important but the student versions of most CAD software used to apply a watermark across any drawings made with the student version when you fed them to a printer. I don't know if they still do but it was intended to prevent use for commercial purposes. The watermark may very well obscure some important dimensional/tolerance information. You may want to test print a hard copy of this before counting on it to do what you want it to. No idea what will happen if the student version file is used to generate "G" code, might want to test this also.

Thank you. That's a great point. I'm actually an academic staff member, not a student, so I believe I have access to some non-student versions of the software through one of the engineering departments.

rcoope said:

Solidworks, Fusion 360 or OnShape would all be fine. I must assume that this is part of a larger project though so don't you have to have a lot more CAD drawings?

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I have access to Fusion 360, so I'll go with that. I'll have to work through some tutorials. The rest of the project already exists; this is a modification/improvement in order to increase load capacity from 10lb to 100lb downward force at speeds of up 40mph with turns.

rcoope said:

My rule for 7075, and this is in no way scientific, is that if you think you need it over 6061-T6 you are into a realm where you should have calculations to show this is the case. 6061 and 7075 have similar elastic modulii at about 10,000 ksi so stiffness will be the same, and even at a yield strength of 35,000psi a 7mm 6061 bar will yield at over 2000 lbs. So you could go lighter with tubing, but cracking might be an issue when you bend it. 2024 is also an option as its UTS is in between the other two. Various bike parts get machined from it like stems. 4130 is Chromoly steel and has a high Young's modulus albeit at 3x the density. But I bet you'll be able to do something clever with tubing there and get great stiffness if that's a consideration. Do give thought to relaxing your 7mm constraint to allow for 5/16" (7.9mm) though, Or even 3/8" (9.35mm) as then you can get .065" wall 2024 tubing which would yield at 2,850 lbs. I see on McMaster you can't get rod or tube in 7mm so you'd have to turn it down which is not totally trivial as the part is long and thin.

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Thank you for the info. I have a copy of Mark's handbook which I've never used, and some text on statics with a chapter on structural analysis; I will look at both. Some tools for analysis may even be built into Fusion 360.

The bends can be anywhere from 10-15 degrees (they're there for clearance). I may be able to eliminate the bends and go with a larger diameter if I can come up with an alternative attachment. I may be able to add some slightly shorter secondary struts as well to form a triangle.

Are there people here that are willing to take on such machining projects once the details have been resolved?

I consider my original question answered by Fusion 360.