Cutting & Packing Workshop

Spring 2008

Furniture Manufacturing

Wooden Frame

Wooden Frame

Wood Cutting

Fabric Cutting

Foam Cutting

Movie: http://www.youtube.com/watch?v=-CnUjwqKUDw

Assembly

Assemble wood frame & springs

Cochins and Textile cover

2D Cutting

Wood

Metal

Textile

Foam

CNC Router

Heads

Hold-down system

Tables

Tool changerController

Accu-Router Movie

Fabric Cutting

What does it have to do with computational geometry

Given a set of 2D shapes (polygons):

place the shapes on a material such that they will not intersect.

Variant #1: Use infinite roll with a given width.

Variant #2: Use sheets of material with a given width and length.

Optimize your solution to use as little material as possible.

Business Value - Example

Bassett Furniture (http://www.bassettfurniture.com)

$300M in revenue per year

13 routers

Cuts ~650K sheets for ~650K frames.

$13M cost of wood

$26M cost of foam (outsourced)

$26M cost of fabric

Total $65M material

 Saving 5% wood material = $650K per year

Different approaches to the nesting problem

Manual nests (or semi automatic):Human made

Automatic nestsSoftware made

Static nestsNest few kits and use the same nest again and again

Dynamic nests

Dynamic approach

Advantages:Nest according to demand.

Nest the exact amount of needed parts.

Support custom styles.

Mix different jobs of the same material.

DisadvantagesA lot of nesting work – requires software.

Each nest is different – sometimes cause difficulties in production process.

Example – build you own furniture

http://www.bassettfurniture.com/tools/custom-upholstery/custom-upholstery.asp?type=loft

Additional Options

Keep grain direction: part cannot be rotated.

Stripes and plaids

Additional Options (cont.)

Hold-down systems & cut order (wood)

Vacuum

Rollers

Flexible

Fires (cut path)

Movie: http://www.youtube.com/watch?v=-CnUjwqKUDw

Foam (cannot leave material during cut)

Stacking (foam) – Cut time/ efficiency trade-off

Leather – quality areas

Metal cutting – Laser Machines

Laser cutting

Movie

Restrictions:Heating

Tabs – holding small parts

Small parts first

Metal Cutting – Waterjet machines