parametric design

[miketo]

hello,

I am a mechanical designer , who build tipping trailers with solidworks 2003.
I want to explain my way of modeling, to share it with other
solidworks users.
We have 7 types of trailers ,each trailer is unique.
The basic dimensions can change.
I did the following things to model a parametric trailer :

1.I make a part named : 15000-reference part-chassis.
This part contains only sketches,planes,axis
The sketches have no features.
They reflect just as good as a 2D drawing of the chassis.

2.The first part in a parametric assy is this reference part.
I insert a extruded profile(for example : 15000-chassis beam left.sldprt)and make the cut extrudes on the profile with the converted sketch lines from the 15000-reference part-chassis on a new sketch in the inserted part.
Some parts are made in place (converted sketch lines from the 15000-reference part-chassis).

3.The assy who doesn't have client specificated dimensions, does't include the reference part.(standard pieces).
It have also no number before the disription name.
for example : spare wheel.sldasm

4.The complete chassis (15000-chassis.sldasm),contains now a combination of parametric and standard assy.

5.With a VBA written input screen, we change the dimensions of the sketches an planes of the 15000-reference part-chassis.(can also be done manualy)
So the dimension of the parts who have external references changes.
The position of the standard assy can also be changed.

6.To make a copy, it is simple:
I save 15000-chassis.sldasm to 16000-chassis.sldasm and replace 15000 to 16000 in the reference box.
(now also be done automaticly with VBA)


So this is my way of modeling.
Is there anyone who have sugestions about this ?
Thanks in regard.

 

[CorBlimeyLimey]

Their are many different methods, systems & preferences which people use to design their products. SolidWorks is just a tool which helps in that design. Many times there is no right or wrong way, just alternatives. If the setup you describe works, without problems, for you & your clients then thats the right way for you.

"If it ain't broke, don't fix it."


CorBlimeyLimey, Barrie, Ontario.
Don't Take It Personal, Have Fun While You Learn
faq559-863

 

[TheTick]

The idea of having master sketches driving assemblies is key to some types of design. I find it is much easier to change a model whose features are "hanging off a skeleton" than one that just "grew out of thin air".

We design hinges, which are an odd challenge. They are spec'd and built as parts, but are truly assemblies. Having master sketches and using envelope components to build base geometry really helps keep these models robust.

"Great ideas need landing gear as well as wings."--C. D. Jackson

http://www.EsoxRepublic.com

 

[JNR]

Are you doing SW assembly cuts? If so it seems like an odd way to do the job. Forgiven me for saying so , but it is a little difficult to understand exactly what you are describing - I assume English is not your first language?

Both CorBlimeyLimey and TheTick have very good points.

It seems that your trailers are all the same basic deisgn but different sizes. I would think that Design Tables might also be a way to go. I assume there is some sizing to do based on stress calcs? You could do that in shreadsheeets/DT's or link it in into them.

Yup, there are a lot of ways to do this.

John Richards Sr. Mech. Engr.
Rockwell Collins Flight Dynamics

A hobbit's lifestyle sounds rather pleasant...... it's the hairy feet that turn me off.

 

[miketo]

No , I avoid assembly cuts.
The cuts are on part level.
Sub assemblys have also configurations with desgn tables.
I just wonder if those features in the driven parts have external references from the master sketch could give problems with performance en rebuilding the parts.

English is not your first language,i am from belguim.
Tanks for the reply

 

[colinp]

Miketo,

What you have described is a very good practice when dealing with large assemblies. This is a standard technique for managing external references and reducing regeneration time. In some software this is called a skeleton model and the sketches are called layouts.

The larger assemblies get the more important managing references becomes. We have some models (created before we started paying attention to assembly management) that take nearly half an hour to open even though they have less than 3000 components.

This is a great tip.

Best Regards- colin

 

[JNR]

Belgium... nice country, good people (I'm an ex-Brit).

Colinp is right skeleton sketch parts do not slow you down and they really help. We have a design tool that uses serveral skeleton parts to define the optical and mechanical goemetry configurations of our systems. They drive the entire design, including location and size of parts and assemblies/subassemblies, complex mechanism geometry (with hinge axes at compound angles). It can even change the number of (sequential) links in the mechanism. It allows us to iterate designs very quickly. it is alos driven from a single external spreadsheet linked in to individual design tables in parts and assemblies. (We do HUD's with Combiners that have to swing out of the way of the pilot's head in a crash and fold up into wierd spaces in cockpit ceilings for stowing.) Your stuff should be pretty straightforward. You need to sit down and determine all the requrements fist, then how you are going to define and drive them, then the data input method. i did a presentation on this at a SW World several years ago. I'll see if I still have a copy and let you know.




John Richards Sr. Mech. Engr.
Rockwell Collins Flight Dynamics

A hobbit's lifestyle sounds rather pleasant...... it's the hairy feet that turn me off.

 

[miketo]

Thank u all for the reply !!
JNR I am verry interested in your presentation.
My mail :

michael.tokmaji@pandora.be