Piece Labels

The argument for printing and placing labels on cut pieces is simple, “The time saved not having to figure out where the piece goes offsets of the cost to print and apply the labels.” Piece labels are most often used by truss fabricators that look for every possible way to eliminate delays in truss production.

Because the labels need to be in the same order as the pieces coming off of the saw, piece labels are created by first running the saw work through a batch cutting program. The program orders the pieces and then creates a “label file” with the piece sequence and the other information needed to create the label (the truss and piece ID, the geometry of the piece, the geometry of the truss and possibly more information.)

The label file is then loaded into a piece labeling printing program that uses the information to print a customized label for each piece. Unlike truss labels, the piece labels only need to be “tough enough” to make it from the saw to the table. Some fabricators like to have a label on each piece, other prefer “one label for every 10 pieces,” and still others believe that “one label for each unique piece” is sufficient.

If you have a lineal saw, this doesn’t work as smoothly. Since pieces are re-ordered by the lineal saw software, the best you can do is print the labels and ask the lineal saw catcher to match the label to the correct piece as it is cut.

If you decide on printing both truss and piece labels, should you plan on using the same printer for both? Although that seems like a logical approach, it may be better to have two printers. Almost certainly the truss labels will need to be more robust (and expensive) than the pieces labels, and dedicating a printer to a single kind of label means there is no need to switch “back and forth” between label types.

Although printing the labels right at the saw seems logical, many prefer to keep the label printers in the office and pre-print them as needed. Office-based printers do not need to withstand the harsher environment of the plant. Once source for labels is 

Labeling Solutions

Above are two examples of piece labels. In the first example we see graphical images of both the piece and the truss. Although it may be hard to see in this example, the piece is “highlighted” in the truss, so as to make clear exactly where this piece goes. This plant also identifies how many unique pieces are in the batch.

In the second example, the plant prints one label for each piece ID – whether it is one piece or one hundred. In this example we also see the sawyer’s name displayed – perhaps helping reinforce the feeling of accountability.

Order in the World of Machinery Files

Although the component manufacturing machinery world is rather quiet at the moment, it wasn’t too long ago that new pieces of computer-driven equipment, from a variety of suppliers, were coming into the marketplace at a rapid pace. Each piece of equipment seemed to have its own file format to drive it, and this presented a problem for both the equipment maker and the design/production software provider (like MiTek or ITW.)

For the guy making the equipment, the choice was either to create their own file format to drive the equipment or piggyback on to someone else’s file format and use it. Because programmers usually prefer creating their own tools, MiTek, Alpine, Virtek, Hundegger, and Koskovich all created different saw file formats. The problem then became supporting all those formats. No two are the same, and they could potentially change without notice. The cost of supporting each new file format was borne by plate manufacturers. A very inefficient system!

Having so many formats and depending on other companies to “get them right” really didn’t benefit anyone. Saw manufacturers found that the cause of bugs or inconsistencies was hard to pin down, and cost everyone time figuring out, “Is it the machine or the output from the design software?” Needless to say, this was also a big pain the people that owned the equipment! Saw makers also found they had to support formats other than their own to gain acceptance. Hundegger had their own format, but programmed their saws to read different saw file types in order to make their products more marketable.

Once established, file formats could become a straightjacket. Koskovich, for example created a simple file format years ago and all the plate suppliers supported it. This file format is simple and clever, but is incapable to such simple expansions as “three cuts on one end,” bevels, and detailed, user-specified piece orientation. Eventually it had to be abandoned. Although programmers might like the control of having their own file format, their companies had marketing issues when attempting to sell a saw whose format initially no one supported.

Around 2005, MiTek and Koskovich began discussing the possibility of a single file for the entire industry. The problem: no file format currently available was suitable. The solution began with the introduction of the Hundegger file format that supported the extra milling tools offered by that saw. Since Hundegger needed to be able to describe a piece with virtually any cut, hole, notch or bevel in it, they created the first truly robust piece description format. After considering for a time the idea of simply nominating the Hundegger file as ‘the standard,’ Koskovich instead created their own format, now used on the Miser saw, as their “can do all things” saw file.

In the last two years we’ve seen a major falloff in the introduction of new equipment. But when new equipment is introduced in the future, there is no longer any reason for a manufacturer to create an entirely new format to support it. There are several well-established ones, including the Hundegger and Miser formats that can describe virtually any piece. The bottom line for the component manufacturer: any piece of equipment you buy from any well-established equipment supplier will work with any design / production software you currently use. At some point, we may even see the day when SBCA officially sanctions one format, which would be of benefit to everyone.

Is it worth keeping an old, inefficient saw in production when the work could be done on a more efficient saw?

Here is another thought experiment. Let’s say we have one saw that takes 20 seconds to set up, and another that takes a minute. We are now dividing up the work between the two of them, to keep both as busy as possible. Would we be better off retiring the old saw and just using the new one? I’ll present a method to answer that question and invite you to apply that method, using your own numbers, to your shop.

Let’s quantify several things about each saw.

1. How long does it take to set up a new piece, including the time between when the last piece has cleared the saw and the operator (or computer) initiates the next setup?

2. How long to set up a new piece if the new piece is also a different size (2x4 to 2x6, etc.)

3. How long to run the last piece through the saw before the next setup can be started?

Once we have these saw metrics, let’s look at the work we are doing. When we do, let’s make sure we get the number of:

1. Pieces

2. Length changes

3. Size changes

The two together will enable us to estimate how long it will take to cut the work on each saw.

We will make up some numbers for our ‘thought experiment’ saws:

The “sample job” MiTek distributes with its software has about 50 different roof trusses in it. Using the default sorting routines, the job breaks down as follows:

Let’s assume this is a typical job, but perhaps it isn’t a typical job for you! The only way to know is to run the numbers on your own jobs and see what you get. Moving on… Let’s see if we can come up with a plausible way to estimate the time it will take to cut this work. We’ll use numbers from the Old Saw first.

· The job begins, the saw sets up (30 seconds)

· The saw cuts (3.1) pieces (on average) and each one takes (2 seconds) to cut

· The saw takes (20 seconds) to clear

· Total = 56.2 seconds

This is repeated for each new piece (303) so the total is 303 x 56.2 seconds = 17028.6 seconds. Add to that 4 size changes for another 120 seconds (4 x [60 seconds for the size change – 30 seconds for the length change already accounted for]) and you get 17148.6 seconds or 4.76 hours.

Now, we will work the problem using New Guy numbers.

· The job begins, the saw sets up (15 seconds)

· The saw cuts (3.1) pieces and each one takes (2 seconds) to cut

· The saw takes (20 seconds) to clear

· Total = 41.2 seconds

303 new setups x 41.2 seconds is 12883.6 seconds plus 20 more for the four size changes and you have 12906.6 which is 3.59 hours.

Presented as a chart, this looks like:

About 33% less cutting time on the New Guy compared to the Old Guy. If they split the job up 50-50 (151.5 piece setups each) then the New Guy would be done with his work in 1.8 hours and the Old Guy would finish up in 2.4 hours. In order for them to finish at the same time you would have to give New Guy about 175 of the setups and the Old Guy about 128. They would both get done after about 2 hours. Putting this all in a chart:

In conclusion, it would seem that the least expensive way to cut the job is to have the most efficient saw cut it – and shut down the older saw. This is only true if the one saw can keep up with the shop. The two saws, working together and splitting their work more or less in proportion to their efficiency, would be able to cut four jobs like the “sample” job in eight hours. The New Guy saw, working alone, would only be able to cut 2¼ “sample” jobs in the same time.

We’ve only scratched the surface here. What about comparing costs when we give the Old Guy only “quantity greater than 10” work and give the rest to New Guy? Hopefully this method can be the starting point to your own investigations and lead you to new ways of thinking about how you use your component saws.