Friday, September 19, 2008

Designing for the CNC process

CNC Design

Introduction to Design
Designing is arguably the most important step to the CAD Process.Why is that you might ask?  Because it is at the beginning.  This is the planning stage of the process.  If you come up with a bad design, all of your work after this point is lost.  I also think of designing as the planning process.  You need an inventory of what you have to work with before you begin.


Every thing needs some planning to start with.Whether it is buying a home or a family vacation.  CNCis no different.  You need to think about what you want to accomplish before you ever invest any time or money.  Now I am not saying you need to have a perfect plan.  What I am saying is that you need to at least have a plan.  Believe me I have had many plans and virtually none of them ended up perfect.  What it did do was give me a guide to follow.  A roadmap of sorts.


You also need to know your limitations.  For example, don’t go designing a metal sign if you have a CNC Wood Router and nothing else.  Or, you want to make a 2” thick wood routed sign, but your CNC Wood Router only has 1” clearance.  You will need to know you own personal capabilities and your shop’s capabilities.  Once you know that, you can improve your situation either through training or purchasing other tools.

Where do good design ideas come from?
First, look around.  Take an interest in your environment and all the various objects around you.  Look at how things are built.  Generally, I don’t look at the overall design.  I try to figure out how they build a specific part or area of the design.  For example a unique latching mechanism.


A lot of good design is experience.  Experience comes from failure as many people have said.  The bottom line is you need to try stuff and experiment with ideas.  Pick the ones that are useful and go with them.  Leave the failures on the scrap pile and move on.  Never marry yourself to an idea as being perfect.Pretty much everything can be improved in some way.

Know what you want before you build it
When designing it is very important that you know what you want to build.  You don’t need to know every detail, but it helps if you have a general idea.  For example, the item may need to fit inside a certain dimension.  This dimension could be the size of the box used for shipping the item to the customer.  This is a requirement of your design.  Requirements can either be self-imposed or put upon you by someone else.


Another example may be building a piece of art.  You may want to make the piece out of Stainless Steel because it would reflect the sun and hold up in the environment.  Then you find out Stainless Steel is too expensive and that you don’t have the equipment to work with it.Stainless steel usually maxes out your equipment.


You need to have a plan, at least a rough one.You will need to look at your skills and match your designs to them.  You will also need to get all requirements for the project before you ever begin.  If you do that, you will not waste extra time redesigning again and again.

What are the limits?
Really, you are the limit.Your brain and its thinking ability are the limit.  If you can think of it, someone, somewhere can probably build it.  The more you expose your brain to different things and ideas, the more connections it will draw.his is where your creativity will generally come from.  You need to feed your brain interesting information and it will spit back some interesting designs.

Part vs. Art
In designing for computer numerical control, there are really two different paths to follow.  Art or Part.  By art, I mean a design that may have extra embellishments, curves, features, text, etc.  By part, I mean a square with a hole in it.  Or a triangular gusset.Art is generally a little more flowing or of an image of something.  It could also be a sculpture for example.


When you are designing art, you normally keep a sketchbook with your ideas.  You note them.  They don’t have to be perfect, just roughed out.  Sometimes I cut things out I find interesting and put them in my sketch book.  Things like interesting shapes, interesting images or even a unique way to bolt things together.


When you are designing parts, you are dealing with deadlines and customer requirements.  There are no extra things to personalize or stylize the part.  The part is utilitarian and gets the job done.This is mainly what computer numerical control is used for.  This is what various industries use CNC for.

Designing on Paper
Most people scratch out their initial ideas on paper to rough them out.  I like to draw things out in a print, drafting or blueprint format.  This style uses multiple looks and multiple angled drawings to convey what you mean to someone else.  I picked up this style of drawing while working in a manufacturing environment.  Some wood workers will also recognize this style.  Think of a time when you bought “The Plans” to building a birdhouse.

Designing with a Computer
This is what I use next.  Once I have something roughed out, I like to translate it into a computer.  Things are more exact.  You get a feel of the size or how parts fit together.  You also get the benefit of saving your work and coming back to it later.  You can even share your files with others when working on a project.

My Design Computer Setup
A few people have asked me about my design setup at home.  Here is what I like to use.  First a powerful computer with plenty of processing power.Be sure to get a lot of processing power, random access memory and a big hard drive.Don't skimp out here.CNC software will use a lot of system resources and you will save plenty of time by having a computer that can handle that extra load.


Next, buy a dual monitor setup.  You will need a graphics card with a dual output head and two monitors to output to.Most users can install this by themselves.  Dual monitors keep you focused.  I really like being able to keep my computer screen clean of various design palates that seem to clutter it up.  A dual monitor is perfect for this.

CNC Information Free Community Site:

If you would like to know more about CNC, head on over to http://www.cncinformation.com You can join for Free and you get two free CNC ebooks. One is a GCode Quick Guide and the other is the CNC Info Site eBook. You also get access to the Free Video Series...Image to CNC Art when you join the community.

No comments: