QC: One Size Fits All


QC: One Size Fits All

When Goldilocks went to the bear’s house, it took her a while to find something that fit her just right. Fortunately, whether you’re a large manufacturer, a small one, or somewhere in between, a formal in-plant QC program is always a perfect fit. In this second article of our series looking at QC, we reached out to component manufacturers of all sizes and asked them about their experiences using the In-Plant WTCA QC program and TPI’s third-party inspection services.

In particular, we asked them about the challenges they faced implementing the program, how they overcame them, and what tangible benefits they have witnessed now that their program is up and running.

Making the Transition to Formal QC

As the first article in this series discussed, the purpose of a formal QC program is to help ensure you produce a consistent product where quality variation is well managed. For instance, the In-Plant WTCA QC program focuses on constantly collecting key data so that you can manage your operations better and make targeted decisions on what areas to address with relation to QC. Without that data collection and analysis, it’s much harder to determine correctly how and where to fix a recurrent production issue.

“Before we started using the In-Plant WTCA QC program, we had a decent in-house QC program,” said Terry Lillard, Plant Manager for Sun State Components in Surprise, AZ. “However, we didn’t have any overall coordination, and we didn’t do regular inspections.” So, what was the biggest challenge in making the transition? “Getting the right person in place to take responsibility for coordination,” answered Lillard. “Once we had that person, the rest was pretty easy.”

Proper data collection can be another challenge. “When we first started using the In-Plant WTCA QC Program 15 years ago, it was a bit more challenging because we couldn’t pull all the data as easily as we can now with the capabilities in the software,” said Dave Rocke, owner of Bear Creek Truss. “Today, the capabilities of the software make it so much easier.”

Finally, timing can play a big role in the level of success you have with a formal QC program. “We started our company in late 2007, which was a huge challenge in and of itself, but we strove to get our WTCA In-Plant certification right out of the gates, “ said Steve Wangen, Design Manager at Gold Standard Truss. “Given our name, Gold Standard Truss, we wanted to establish ourselves as a step above the rest, and the QC program was vital in helping us accomplish that.”

In-Plant Inspection Basics

The most important aspect of a formal QC program is the in-plant inspection. At its most basic level, an in-plant truss inspection compares a finished truss to the truss design drawing (a.k.a engineering drawing), its related joint details, and quality criteria in the building-code-referenced ANSI/TPI 1, Chapter 3. The observations collected from these random inspections are key in helping you identify areas in your production process that may need to be addressed in order to reduce or eliminate product defects.

“We were fortunate in that we brought in experienced staff from all over, and most of them understood the advantages of using a formal QC program and having regular QC inspections,” said Wangen. “Starting when we did, we had to establish our niche quickly and impress our customers right away, otherwise we weren’t going to survive. The QC inspections helped ensure our product was impressive.”

There are really only two main steps to in-plant truss inspection.

Step 1 is to perform a preliminary truss inspection of the chord and web members, plated joints and then the overall truss. The inspector should look at 6 key areas:

  • Truss dimensions
  • Lumber species, size and grade
  • Plate size and gauge
  • Plate rotation
  • Plate embedment
  • Wood member-to-member joint gaps

The preliminary inspection should also ensure that the truss matches what is specified on the truss design drawing.

Step 2 is to perform a detailed joint inspection. The purpose is to examine a specific joint in more detail to verify items that may not generally be noticed in a preliminary inspection covered in first step. The items to specifically address in a detailed joint inspection include:

  • Plate rotation
  • Midpoint location of the plate on the wood member joint
  • Knots, wane, etc. in the plate area per wood member at a joint
  • Number of teeth per member (if applicable)

During the detailed joint inspection, findings are compared to the Joint QC details.

In most instances, more than one joint will be inspected. The specific number of joints to inspect is outlined in TPI 1 Chapter 3, which states that a minimum of one critical joint (a joint with a joint stress index (JSI) of 0.80 or higher) per truss should be inspected, on average. In practice, more than one critical joint is inspected, since it provides greater feedback on the assembler’s ability and consistency in accurately placing plates.

“We have one person doing in-plant inspection once a week. Our employees know that if something comes up it’s going to get back to them, so they’ve gotten good at policing themselves,” said Rocke. “We’ve also used TPI to do our third-party inspection process because it’s required by the building code for the jobs we do. We’ve stuck with TPI because they’re at the forefront of the third-party QC inspection process for the truss industry.”

The Tangible Benefits of QC

Make no mistake, implementing a formal QC program takes a commitment of time, energy and resources (though not as much as you may think). However, in talking with component manufacturers who have a formal QC program, the tangible benefits far outweigh the investment. It all starts with the customer.

“The work we put into our QC program translates directly to our customers. They comment on how nice our trusses are; how good they look and how well they fit,” said Wangen. “We don’t have customer callbacks attributed to mistakes made in the production process.”

Beyond a happy customer, the QC culture developed by a formal program has significant impacts on the production efficiency and employee pride. “WTCA’s In-Plant QC program helped us fine tune some aspects of our production process,” said Lillard. “We use roller gantries, and the QC program made us more cognizant of checking plate placement and embedment, particularly on the back side. It’s also helped our end line guys identify quality issues and has given them a quantifiable process to send trusses back to the production line. In turn, our production guys pay closer attention and fix problems immediately because they don’t want trusses coming back to them.”

“Having everyone aware and invested in the QC program means there’s no question if something is ‘close enough.’ Through the program, everyone is aware of the tolerances allowed; there is no gray area, so everyone is focused on if it passes or not,” said Wangen. Echoing Lillard’s comments, he added, “we have line monitors that watch all the QC issues, and if something out of tolerance gets built and fails inspection, our production guys know they’re going to be fixing it before it leaves the yard. So they take the time to do it right the first time.”

“Our QC helps us identify employees we can trust to take responsibility for the production process,” said Santiago. “It allows us an opportunity to empower employees to take pride in the ownership of our product. They have the authority to evaluate material and discard it if they think it will create a QC issue. When in doubt, throw it out.”

Lillard said virtually the same thing, “Because of the culture we’ve created through our QC program, our production guys are always looking at the condition of the wood in the plate area. They’re all empowered to toss stuff out at any time. That puts more responsibility on our sawyers and pickers to not put bad lumber into the system in the first place.” Lillard added that he’s worked at a number of plants over the years, but he’s never taken more wood out of the system than he does at Sun State Components. “Fortunately, it all ends up getting used somewhere eventually.”

One additional benefit of having a formal QC program in place is the inherent training built into the process. In the hands-on training you provide to your employees, they learn how build a truss; a formal QC program enhances that training. “QC exposes your production guys to the tolerances of truss design and explains why member gaps in joints, rolled teeth and insufficiently embedded plates are a big deal,” said Dave Motter, Chair of SBCA QC Committee.

Making an overt commitment to quality also changes the focus of your employees. “If you measure the success of your company by how many board feet of components you produce, that will be the thing your employees focus on,” said Motter. “You have to accurately measure quality in order to convince your employees to focus on it. The In-Plant WTCA QC program helps you do that.”In talking with component manufacturers who utilize a formal QC program, that focus on quality fostered employee’s sense of pride in the product they manufactured.

Peace of Mind

The bottom line is this process builds trust in the quality and code compliance you have for the final product you deliver to your customers. “It is so seldom that we find problems that need to be fixed now,” said Rocke. “As an owner, that gives me great peace of mind.”

Whether you’re a big operation or a small one, the real benefits of having happy customers and an efficient production process make the investment in a formal QC program a wise, and comforting decision.