Paper drawings to DWG possible??

[John Stevenson 1Participant @johnstevenson1]

Yes i agree with things like mobile phones but you only make one mould, Engine blocks are again done as one off's and then cast.

It's the general run of the mill parts that are done in thier millions that work on 2 1/2D.

 

There are machines out there like the Bridgport clone based machines like the Protrak that you program conversationally at the control, some of these don't even have a powered Z axis and are literally only 2D with Z being worked by hand.

The Hurco which is a full 3D machine can also be programmed at the control and has one of the best conversational programming out there.

If you say that it's only 9% done in 2 1/2D then I and a lot of companies I know have been very busy for the last 20 years.

In fact Solid works, Pro- Engineer and Inventor haven't been about for this long, The only 3D programs that were about this long ago would have been impossible to buy for even a medium sized business.

 

It's incorrect and throwaway remarks like your original statement that put beginners off from having a go with CNC. They read one mans incorrect interpretation and think "I can't do that" and that's another beginner lost to the hobby.

 

You are also missing the main point in slagging off Draftsight in that it's a CAD program, CAM is responsible for generation the G code and depending on what CAM you use determines how complex the tool path is.

 

Not Draftsight but could have been drawn in Draftsight it's that simple.

 

Just a circle and a cross, copied twice.

Now in CAM if we select merge we get this.

 

 

Dependant on which profile we give a positive value to and which way we decide to machine it determines the shape.

 

Now imagine if we took your mobile phone model and sliced it, then processed the slices.

 

Or the pattern for a loco cylinder block.

 

Please do your homework BEFORE making sweeping statements that are incorrect, it only harms the hobby

 

John S.

 

[EDIT] To bring things into the cold light of day and following Pauls advise be prepared to pay about £5000 for solid works or inventor, probably £11,000 for Pro- Engineer.

Then you need a capable 3D CAM program to process the 3D drawings and last quote I saw for Mastercam Level 3 was also £11,000.

Edited By John Stevenson on 05/08/2012 10:41:21

[Paul LousickParticipant @paullousick59116]

John,

My original statement was for comments about CAD programs for which I have been using for over 20 years (Autocad Release 9 to Autocad 2012, Pro Engineer, Microstation, Solidworks) ,so I HAVE done my homework AND do have some experience in these matters. I stand by my statement that Autocad is far superior to Draftsight. It must be it's £5000 more expensive. If Draftsight was better Autodesk would be out of business. This in no way is "slagging" Draftsight. It is excelelnt value for money , its free to download. We even use it where I work for viewing and red-lining drawings.

And as I have previously said, Draftsight IS suitable for transferring paper files to CAD and exporting dxf files to CNC machines which only require 2D input (and minimal extra programming). It is not suitable for cutting complex shapes/contours,fillets, etc on a CNC milling machine without the input of a lot of extra programming.

Paul.

[John Stevenson 1Participant @johnstevenson1]

Posted by Paul Lousick on 05/08/2012 12:13:15:

John,

 

And as I have previously said, Draftsight IS suitable for transferring paper files to CAD and exporting dxf files to CNC machines which only require 2D input (and minimal extra programming). It is not suitable for cutting complex shapes/contours,fillets, etc on a CNC milling machine without the input of a lot of extra programming.

Paul.

.

Paul,

It ISN'T the job of the CAD program to control a CNC milling machine.

That process is handled by CAM as I showed in the post above and as you can see from the process tree on the left three operations is not " a lot of extra programming "

 

Now whilst I concur that as a user you have a lot of experience I do question if you have hands on CNC experience in a day to day working environment ?

 

I question this because if you are a CNC user you will know that your sweeping statement is incorrect, a view also held by Graham Meek who's work and experience speak for itself.

 

Just because it costs £5,000 more it doesn't mean to say it's any better, just more expensive. and as regards whether they would still be in business the truth is it has got to be hurting them, on your own admission you are using a copy of Draftsight instead of paying another £5K for an extra seat.

How many more are in that position ? How many thousands of times has DS been downloaded? Then times that by £5K

 

John S.

Edited By John Stevenson on 05/08/2012 12:33:34

[blowlampParticipant @blowlamp]

The original poster was asking about transfering 2D drawings of Netta to CAD so it seems like only a basic program would be needed.

I doubt there's a single part on that model that would be better made by using a 3D CAD/CAM/CNC system.

Use 3D CAD and CNC machining for curvy parts, such as aircraft, car bodies and other funky shapes, but use 2D for almost all the other common stuff like sprockets, clock parts and all manner of linkages, as well as awkward shapes such as ellipses and cams etc.

Martin.

[John Stevenson 1Participant @johnstevenson1]

Also remember that in 3D machining you are using small cutters with very small offsets so the curves blend in. It's not out of the ordinary on home shop machines for a file to run 11 hours or plus.

Industry gets round this by running 42,000 rev spindles and insane feed rates but we are not privvy to these features or the money they cost.

So do we spend 1 hour on a 2 1/2D part and a bit of hand filing to blend in or spend 11 hours because we can ?

Fillets are perfectly possible by using radiused or ball nosed cutters so a lot of detail can come straight off the tool.

[Paul LousickParticipant @paullousick59116]

As Blowlamp has said, the original poster was asking about transferring paper drawings to CAD and I advised that they can be imported into vector format but will not be to scale. And if you check my first posting you will find that I did recommend that he use Draftsight. The following comments were intended to show that it was not the best product available but would be suitable for his project.

Draftsight is one of the better free CAD programs available but is not in the same league as others like Autocad. We have more than 120 licences of Autocad and 50+ copies of Draftsight but Draftsight is only used by our sales engineers and non-drafting personnell to view, print and make small changes to drawings. All of our professional drafters in our drawing department use Autocad or Solidworks because it is more efficient for full time use, far outweighing the extra cost. But for small projects where time is not a problem, use Draftsight. I could go on for a lot longer but am putting this discussion to rest. I am sure that you still have something to say, so will leave it to you.

Paul

[KWILParticipant @kwil]

John S. You should remember, the draughtsman is always right, it is the shopfloor that sorts out the problems and then tells the draughtman the corrections necessary.

[John Stevenson 1Participant @johnstevenson1]

Best to do the drawings from the finished part, that way they will be right !

My argument wasn't about CAD and the differences between Autocad and Draftsight but Paul making an assumption in the field of CAD/CAM that was totally incorrect.

The problems are once something is published on the Internet it then becomes gospel and I for one don't want someone taking a look at Solid works / Inventor / Pro Engineers and thinking "I can't do this " and writing off CNC based on one persons misrepresentation.

Until Paul's post about Draftsight not being suitable for CNC [ which it IS ] CNC hadn't been mentioned.

John S.

[Robin teslarParticipant @robinteslar]

I used Acad when it still ran under DOS (v14). It was simple and worked and never crashed. Then it converted to Windows and GUI and it was not a happy marriage at first for many reasons mostly based on its former DOS background. I now have ACAD 2009 which functions but Ive sweated blood over it, and theres quite a learning curve there. Frustrating when you just want to get on and make an engineering drg and do the job, Scanning is not an option for a dimensioned drg – period. If Draftsight works, then go for it. Ive also come across Progecad and used the free 30 day trial version. Its a clone. Found this

**LINK**

Seems too good to be true, but I notice that they do some DVD training vids. Ive used these to master Photoshop (its a pig to learn from Adobe) and found them a very effective training method

Its difficult to maintain fluency with Acad unless you use it regularly. After a months absence it hurts my brain to get started again.

 

Oh sorry pardon I missed some of the earlier erudite posts from professional cadmen.  I gave up trying ACAD for 3D but it was an early version.  Instead I discovered Sketchup and if you've never done 3D modelling this is a delight.  You'll get the gist of it in half an hour.  Its free and a lot of fun, bbut its not just trivial toy, you can really learn a lot from it.  Its no good for serious dimensioning but it produces shapes and solids to an accuracy of 13 digits.  For example I was able to construct a 3D perfect dodecahedron (made from 12 pentagons). Try it, then you will know you have arrived.  

http://sketchup.google.com/download/

Oh and btw, there are many plug ins now and one which fascinated me, was

http://code.google.com/p/sketchyphysics/

which puts newtonian physics to work on your model (eg a continuous bicycle chain, a compound pendulum and so on) – fascinating but still in enthusiastic development

Cheers

 

Robin

Edited By Robin teslar on 02/11/2012 11:41:43

[David SkidmoreParticipant @davidskidmore39814]

David Skidmore

I got a set of plans for an 08 in 5"g and find that it would be yo big for me.

How do i change to 3.1/2g

[richardandtracyParticipant @richardandtracy]

The simplest thing would be to mark up a copy of the plans you have with the old dimension multiplied by 3.5/5. If you wish to use stock sized material, you need to find the nearest stock dimension to the 3.5/5 figure and work the changes through all parts that may be affected by the change in size. Not something that advice can be given on without seeing the item

Regards,

Richard

[Author]

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