CNC Chop Saw

Introduction

An automated chop saw has the potential to save 50-75% of the cutting time required for all the dimensional lumber that is used to build a Seed Eco-Home.

The biggest saving with a CNC Chop Saw is the time savings of measurement. Many times lumber is measured, and long lumber takes at least the amount of time to measure as it takes to walk from one end of the piece of lumber to the other. For a 16' piece of lumber, that is 4 seconds at a 3 mph walking speed. Add to this placement of tape (3 s), looking up the measurement (5s), marking (3 s) and then rolling the tape back up - (5 seconds) - this could easily be 15 seconds per marking. Moving the lumber into position takes another 5 seconds, and adjusting on the saw another 5 seconds, for a total prep time of 25 seconds for a single cut. The cut itself would take only about 2 seconds on a sharp chop saw. Then the lumber is placed on a finish cut pile, or another 10 seconds. Counting (inventory) can also take 5 sec as every so often the operator works through an inventory count. Total time to process 1 board: About 47 seconds.

The CNC chop saw consists of an elongated table with rollers where the piece of lumber is placed on rollers, and the lumber is rolled on the rollers until the lumber hits a stop. The chop saw moves via CNC to the desired cut length, and all the operator has to do is turn on and lower the chop saw to cut the lumber. The processing time for one board eliminates the measuring, marking, moving, and most of the positioning. The estimated time is 5 seconds to place the board on the conveyor until it hits a stop, 2 seconds to cut, and 10 seconds to place it on a finish cut pile before being ready to start again. Thus, we have 17 seconds vs. 47 seconds. This saves over 60% of the labor to do the pre-cutting - but also another important effect here is the improved ergonomics (mostly the roller) which reduces operator fatigue significantly. This means that an operator could maintain their rate of production for a longer time, as opposed to, say slowing down by 25-50%. In the conservative slowdown scenario, the worker would take a minute or more per cut, say in the second half of an 8 hour day.

For the automated route using a CNC Chop Saw - the prep time is reduced to placing the piece of lumber from the pile onto the rollers, which hits against a stop, as the saw moves automatically to the correct cutting length. All the operator needs to do is hold the lumber against the stop, and lower the chop saw after turning the chop saw on. The time required for this is

The Seed Eco-Home has about 100 modules - or around 600 cuts. Thi

The typical precutting process involves this process acting upon a stack of different lengths of dimensional lumber:

1. taking a pile of dimensional lumber, measuring + marking lengths, a

Design of CNC Chop Saw

1. Working table surface height is at a comfortable working height for the operator
2. Must have a landing area o top of the working table where raw dimensional lumber is deposited in a rough manner. Preferably, this involves rollers where lumber is slid into place from the working pile. In this case, minimal space is needed, and a single operator could easily take the raw lumber from a pile
3. Fine positioning of lumber from the