emachineshop.com

[darylat8750]

I stumbled on a website for a machine shop called Emachineshop.com, they have a cad program you can download. From what I can tell you can draw up your parts and tell them the material to use and they will quote you a price. Also the more parts you order the cheaper the price. They have water jet and all kinds of cnc tools. I have not tried them yet but thought it might help you guys.


I copied this from another members post... Thanks to Maddog.

 

[cwilliamrose]

I had some parts quoted locally, it might be interesting to have these guys quote the same parts. I see they want the parts for quote done in their CAD software so it can reject any non-machinable features. I wouldn't care to re-create all my SWx models but the software will allow importing of STEP files. I'll report back when I have a chance to get some models to them for quote.

 

[gary nj]

Thanks for your interest in our online machining services. I'd be glad to answer any questions you might have about our services. We have made parts for folks flying planes, helicopters and ultralights.

As far as working with files created in other software packages - we do have an import function, but it is currently a beta version and is not 100% functional. If you have a 2D part and can export from your CAD in a .dxf format, it will work very well. If it is a 3D part, .dxf will usually work, but you will have to make some tweaks to your imported drawing. The .step import is definitely not 100% yet - the geometry of your part will allow it to work anywhere from very well to not at all. Same thing with importing in the .igs format. The following link has more details of the current import capabilities: http://www.emachineshop.com/machine-shop/Importing/page449.html

The reason everything needs to be in our CAD is because the CAD program actually generates the price quotes in an automated fashion, right on your desktop. You can adjust your design, quantities, materials, tolerances, etc all day long and the software will keep updating the pricing. Once you are satisfied with the design and quote, you place your order online directly through the software. The whole process is completely automated. Our CAD is free, simple enough to be used by someone who's never used a CAD package before - we have lots of online videos and help screens to assist you in getting started. And I'll be glad to answer any questions you have as well.

Again, thanks for your interest, and I hope we can help members of this community with any custom machining needs you might have!

Gary
www.emachineshop.com
eMachineShop
Mahwah, NJ

 

[cwilliamrose]

Thanks for posting on our forum Gary. I have just done my first part with your software, using a STEP file import of a simple fitting for a Pitts upper front spar attach. The import seemed to work fine. I specified 4130 annealed for the material (I'd rather see 4130 normalized as a choice). I was surprised I couldn't specify a process to use and the software seems to be defaulting to a process that leaves a draft on the cuts but it doesn't tell me what that process is.

When I went to the quoting step I got a very big number, well above what a local CNC shop would charge to do the same part. I'm not sure why but I suspect the part is being quoted as something other than a sheet metal part. It is .090" thick and would be made from stock of that thickness. The software may be machining all surfaces instead of just the outer shape and the holes. Also, the closest tolerance you can select is ±.005" which is not good enough in some cases like the hole diameters and plenty good for the overall shape.

For me one of the most important things would be to specify the process. In the Job Settings box under Process there are only selections for Injection Molding, Rapid Prototyping and casting. None of these would apply to this part.

Here's a couple of screen shots;





So I guess I'm asking what I'm doing wrong that resulted in such a high quote and pointing out some things I couldn't find. I also wish there was a better way to measure the features of part in your software to confirm an imported part is correct. Beyond that, applying different tolerances to various features might save a few bucks. I suspect much more could be saved if this part could be treated as a sheet metal part.

 

[cwilliamrose]

Gary,

I thought to try a round trip confirmation using the EXPORT feature. The IGES and STEP choices resulted in no file being exported. The STL file was exported at 1000X size. The DXF worked best as it came through properly scaled and matched to original model.

 

[gary nj]

Hi Bill - Thanks for sharing your experiences. If you wouldn't mind, I'd like to see your .ems design file in order to better answer some of your questions. You can email it to me at [email protected].

I can comment on some of your questions without having your file. As to the processes used to manufacture the part - the software actually looks at the design and figures out, based on the geometry and specs, what is the most economical process. This is trickiest with parts which are 2D and/or simple 3D, where multiple processes are possible. More complex 3D and turned parts are easier, since they generally have to be made on a CNC mill or CNC turning center. Without having your file in front of me, it looks like a part which could be produced via a 2D process such as water jet cutting. However, to be produced that way, your specs would have to show you are willing to accept some draft angle on the edge, a looser Ra tolerance on the edge, and =/- .010" on your linear tolerances. If you made them anything tighter than that, the software will decide the part has to be CNC milled. You also couldn't have any 3D features added, such as hole chamfering, countersinking or any edge treatment. I'm suspecting that the software priced your design using a 3D process - I can confirm that if I can see the design file. It is possible to spec your job so it gets produced using the water jet, and then use Comments To Machinist to specify those features which need to be at a tighter tolerance. For example, on your part, the exterior shape may be acceptable with a +/- .010 tolerance, 10 degree draft angle and a 1000 Ra edge.....but maybe the three holes need to be +/- .003" from nominal. You would use Comments to Machinist (CTM) to point to the holes and indicate the required tolerance. The CTM won't get automatically priced by the software - we'll have to manually quote that - but you'll see the system price is much lower. Even with the manual quote features added, it should still be well below the system quote if it is interpreting the job as 3D rather than as basically sheet metal.

Also, as a general statement, quantity 1 is always higher than you might think, because all the fixed costs of the order are being applied to just 1 piece, and multiple additional parts can be produced with relatively little additional costs. That is the nature of manufacturing anything custom, and in the case of CNC, all the programming and setup cost is the same for quantity 1 or 100. Again, the automated price quoting makes it very easy to see the differences in pricing.

Thanks again for posting, Bill, and if you wouldn't mind sending along your file I can comment even more specifically.

Gary

 

[cwilliamrose]

Check your email for the file.

Airplane types tend to be control freaks when it comes to how their parts are made. Apparently the water jet process leaves a draft on the cuts which I would not find acceptable. I'd feel better if I could specify CNC milling for the process because I would know what to expect. I need the edges to be very smooth because it is a structural part that could see fatigue cracks in service. The location of the holes needs to be close and the diameters should be right on -- reamed if I was making these parts manually.

In order to get the part price down to what I was quoted locally for a quantity of two I needed to order about 50 parts on your system. This lead me to believe it was somehow an apples versus oranges comparison.

 

[gary nj]

Check your email for the file.

Airplane types tend to be control freaks when it comes to how their parts are made. Apparently the water jet process leaves a draft on the cuts which I would not find acceptable. I'd feel better if I could specify CNC milling for the process because I would know what to expect. I need the edges to be very smooth because it is a structural part that could see fatigue cracks in service. The location of the holes needs to be close and the diameters should be right on -- reamed if I was making these parts manually.

In order to get the part price down to what I was quoted locally for a quantity of two I needed to order about 50 parts on your system. This lead me to believe it was somehow an apples versus oranges comparison.

Hi Bill - I got your file - thanks!

Your design could be water jet cut for the price you referenced, with you supplying the material, but the specs wouldn't be as tight as you wanted. It couldn't be CNC milled at that price/quantity - you'd need more pieces to spread the programming/setup/QC costs, and get the cost per part down. If you have a local shop willing to CNC mill the parts at that price you're getting a great deal. I know what it takes to make even a simple part like yours, and they are working at a very low shop rate for that price. Was this a 'cash-only' price?

 

[cwilliamrose]

We had planed to do the sheet metal parts stacked so you would get both parts from one setup in this case. We discussed tack welding the blanks together and having the last step remove the tacked areas. They could have also been pinned after the first few holes were in place. Some parts were quoted 8/ea also stacked to save machine time.

I looked at doing these manually and the only real issue was the outside radii. Those would have be done in a crude way compared to a fully CNC part but fairly typical of how other builders do it but still doing them stacked.

We didn't discuss payment methods. I think I need to add at least 2D CNC to the Bridgeport!

 

[maddog]

Sorry it didn't work out, I was trying to give you guys another place to get some parts made.

 

[darylat8750]

Sorry it didn't work out, I was trying to give you guys another place to get some parts made.

I'm not convinced it didn't work out. They may be useful for some parts under some circumstances. I suspect that with Bill's skills and knowledge he is able to get more competitive pricing than many of us. It is good to have options.

 

[christopher]

Looks like a viable option for some parts for me! I can't make everything I need with my little lathe and drill press. Thanks Maddog!