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Richard86
05-05-2009, 07:31 PM
I often build hydraulic operated machines. Example: truck endgates,

folding toolbars, small cranes. I always draw things out on the floor or cut

cardboard to work out the hinges and cylinder mounts. Kinda a trial and error

thing. Does anyone know of a CAD program that might do this for me?

I hate to invest to much, but the time it might save me could be worth it.

Thanks Rich

rubes
05-05-2009, 08:24 PM
I use AutoDesk's Inventor and PTC's Pro/E at work. Inventor, in my opinion, is superior to Pro/E for ease of use. Both of these are real high up on the $$$$ money scale though. However, Autodesk is giving away free 13 month versions to students, which may not help you much.
http://students4.autodesk.com/
Autodesk has an Inventor Lite, but I know nothing about it or cost.

You can buy a personal use copy of Pro/E for $250
http://store.ptc.com/DRHM/servlet/ControllerServlet?Action=DisplayProductDetailsPage&SiteID=ptc&Locale=en_US&Env=BASE&productID=107381300
but be ready for a pretty steep learning curve.

I'm sure there are others, but these are the ones I'm familiar with, and are indispensable for me in product development.

PeteM
05-05-2009, 08:26 PM
CadCalcs might do it. (cadcalcs.com)

Evan
05-05-2009, 08:52 PM
FreeCad has been around for quite a while and is still actively supported by it's author. It's opensource freeware and will handle a wide variety of kinematic problems'



What are the features of 'freeCAD'?
'freeCAD' is capable of full 3D pan, zoom, tilt and rotate. Available solids are extrusions of rectangles, circles, ellipses and polygons. The solids can be positioned and oriented exactly in space, as are markers on the solids. Exact specification of linear and angular velocities of solids in space are also possible. Mass and inertia properties can be user specified or automatically computed based on uniform density. Available joints are spherical (ball), revolute (pin), translational (slider), cylindrical, planar, fixed, universal, point in line, point in plane, parallel, perpendicular, no rotation, constant velocity, rack pinion, screw. Both open and closed 3D loops are permitted. The curve-curve contact allows liftoffs and collisions based on coefficient of restitution. Available actuators are rotational and translational. Their motions are user prescribed functions of time. Forces and torques are user prescribed functions of time, displacements and velocities in all three components or along connecting markers. Example formulas for spring, damper, bushing, beam, aerodynamic, inverse square law and other forces and torques are given. Users can specify constant gravity of arbitrary magnitude and direction. 'freeCAD' can compute kinematic, quasi-static or dynamic solutions based on the assembly and user requests. 'freeCAD' does redundant constraint removal automatically. Simulation progress is animated and the simulation can be stopped any time. After simulation, the computed solution can be used for animation or frame by frame analysis. Full 3D pan, zoom, tilt and rotate is available during simulation and animation. Users can obtain engineering data in the form of plots and tabular output. XY plots can be zoomed and set to equal scales. Data series available include linear and angular displacements, velocities, accelerations, forces, torques, momenta and kinetic energies. Acceleration data include transverse, centripetal and Coriollis accelerations. Users can view forces and torques from joints, constraints, actuators, springs, dampers, applied forces and inertia. Individual parts can be save into files and reinserted into any assembly repeatedly. Assemblies can be saved in binary or human readable, tab delimited, text format with notes and simulation data for later reload. The text format allows pre and post processing of assemblies by other programs, especially spreadsheet programs. 'freeCAD' runs on Windows, Macintosh PPC, Linux PC and other Unix's. Assembly data are unchanged across platforms.

http://www.askoh.com/previous/previous/freecad/index.html

Dave S.
05-05-2009, 09:19 PM
Take a look at Alibre 3D modeling software. You can get a full working copy free.
You can build your parts and then assemble them. By moving one part others will move accordingly.

10KPete
05-05-2009, 11:11 PM
I've been looking for the same thing but anything that really works seems to cost more than makes sense on a fixed income.

In addition to wanting to make the parts move I want to be able to input forces and have the program give me resulting forces.

Will the Alibre calculate forces in the links?

Thanks,
Pete

Edit: I just went to the Alibre web page and see that the program starts at a kilobuck!!! Too much for me.

Silverwolf
05-06-2009, 08:53 AM
I just tried Evan's freecad thing. Its awesome. I have the latest 3d modeling software from Mya,and Z brush, worth several thousand dollars. I got them from my son in law who got them from the Universtity he was at. THe freecad is like Mya for kindergarden kids. Its great. Mya is extremely complicated, took several years to master. I mastered freecad in about 5 minutes, so I figure a complete rooky with this stuff could be designing stuff in about 2 hours with freecad. Good post Evan, I love these programs, now I can get my Son started on some easy stuff first. Thanks again Evan.

BillH
05-06-2009, 10:07 AM
Solid Works is what you want for simulating mechanical linkages.

japcas
05-06-2009, 02:20 PM
Solid Works is what you want for simulating mechanical linkages.

It seems like a lot of people recommend Solid Works for cad and modeling work. It may be a good program but a bit pricey for the average home shop guy don't ya think?

Evan
05-06-2009, 02:30 PM
I refuse to spend that amount of money for software. I have spent thousands over the years but I cannot justify that sort of single expenditure for a hobby.

mochinist
05-06-2009, 02:50 PM
It seems like a lot of people recommend Solid Works for cad and modeling work. It may be a good program but a bit pricey for the average home shop guy don't ya think?He's not recommending you buy it.;)

Find the chubby neighborhood teen and he will be able to help you out

also they are letting you have a trial version to learn with

copy/paste from practical machinist site


In a nutshell, you can download a free version of Solidworks that is valid for 90 days. You can learn the software and get certified for free as well. It's a big file so you'll need a highspeed connection. Quote from the link:

"The SolidWorks Engineering Stimulus Package provides free SolidWorks 3D CAD software to any U.S. or Canadian resident seeking to develop, upgrade, or refresh the valuable 3D CAD skills that employers need. In addition to the software, you get self-support, free training materials, free certification, and job leads."


http://www.solidworks.com/sw/enginee...s_package.html (http://www.solidworks.com/sw/engineering_stimulus_package.html)

Richard86
05-06-2009, 08:01 PM
Thanks for all the replies guys, I knew I could count on you!! I haven't
had time to check them out yet. I have been working on an implement

toolbar for a skidloader with one wing that has to fold over 180 degrees.
Today I've been chopping up particle board into linkage patterns. I just

finished design tonight. Hopefully tomorrow I can get it converted to iron. My problem has been that the time it takes to find a CAD program and then try to learn it, I could have whatever built several times over.

I just need to quit procrastinating and do it, I'm sure in the long run it will save me a bunch on time and particle board . I have to be done by Monday so, not much time to learn.

I will try to post pics next week if anyone is interested. Thats another skill I've yet to try.

Thanks again for the help fellas.

Rich

BillH
05-06-2009, 08:16 PM
I view solidworks as being just as important as having a lathe or a milling machine. It is the 3rd tool.
Yeh, what Mochinist said.

Cheeseking
05-07-2009, 12:11 AM
Could you print off some scaled 2d prints of the linkages on 8-1/2 x 11 paper, cut out with scissors and straight pins or toothpicks for the pivots???? If the paper is too flimsy then transfer to cardboard or something.

camdigger
05-07-2009, 10:55 AM
Could you print off some scaled 2d prints of the linkages on 8-1/2 x 11 paper, cut out with scissors and straight pins or toothpicks for the pivots???? If the paper is too flimsy then transfer to cardboard or something.

They make label paper for address labels. You could print, peel, and stick your patterns...

George Barnes
05-07-2009, 12:02 PM
Not on the subject of software, but relating to the need to make something fold over 180, take a look at the linkage on the bucket of a backhoe. It looks like they get that or maybe a little more by just adding another link between the hydraulic cylinder and the bucket attachment. I don't fully understand what the critical geometry is on this mechanism.

Just a thought.

dfw5914
05-07-2009, 12:37 PM
Could you print off some scaled 2d prints of the linkages on 8-1/2 x 11 paper, cut out with scissors and straight pins or toothpicks for the pivots???? If the paper is too flimsy then transfer to cardboard or something.

Cardboard
Aided
Design

Bob Farr
05-07-2009, 01:25 PM
*** My problem has been that the time it takes to find a CAD program and then try to learn it, I could have whatever built several times over. ***
Rich

If you want to skip CAD for a bit longer, "Link Mechanisms" is a little 35-page booklet that I find very helpful. I paid $6 for it at NAMES. It was originally published in 1908, and republished in 2000 by Nation Builder Books, P.O. Box 253, Leesburg VA, 20178, telephone (800) 480-5808, web site at www.NBBooks.com

Cheeseking
05-07-2009, 01:25 PM
Before we had Inventor and Solidworks we used this software....http://workingmodel.design-simulation.com/WM2D/demo.php
Looks like you can get a demo copy.