There is not a lot of room for error in high-speed cracker production. The faster the line, the greater the consequences if something, anything, is even slightly out of place. Without consistency and control, bakers risk lost product and unnecessary downtime.
“It’s important to keep control of the process within the known guidelines and avoid large swings in the process, which can lead to an out-of-control process and out-of-spec product,” said Andrew Parlour, director of sales and marketing, Bühler.
On high-volume lines, everything becomes more critical: ingredient quality and accurate scaling, dough quality coming out of the mixer, consistent dough feeding and a balanced dough sheet, accurate cutting and spraying. That’s because any inconsistency becomes magnified at such rates.
“At higher speeds, things happen very fast, and quite a bit of dough can be wasted before you know it,” said Don Smith, director of biscuit, cookie and cracker equipment sales, Reading Bakery Systems (RBS).
Consistent dough out of the mixer sets production up for success. Accurate and even reduced sheeting ensures a balanced dough sheet and a consistent bake. But even conveyor speed and precise positioning through transfers aids in keeping the dough sheet moving quickly through the process and minimizes risk of upsets.
Balancing the dough sheet
A consistent dough sheet is always critical for consistent crackers at the end of the line. Uniformity starts at ingredient handling and must be carried throughout processing. Without dough consistency, processing efficiency and final product quality can be affected.
“Any variations will have a direct impact on how the dough behaves when it’s processed and how much further attention will then be required by the operator to maintain a balanced control of the forming equipment,” said Andy Green, technical development manager, Spooner Vicars Bakery Systems. “As production speeds increase, resultant problems materialize sooner and become more difficult to correct.”
Dough consistency starts with ingredients as they are the building blocks of the dough. Mr. Green also stated that to ensure the repeatability of each dough batch, storage and ingredient handling must be optimal and accurate as they are delivered to the mixer. What comes out of the mixer will have the biggest impact on the sheeter as the cracker dough sheet speeds through the gauge rollers.
“One of the biggest pain points in most cracker production is what you get from the mixing room,” Mr. Smith said. “If your dough is not consistent coming out of the mixing room, then you’re going to have problems running it through the machine and baking it.”
As dough enters the sheeter, it’s vital that it is reduced to the proper thickness across the width of the line. This prevents any product weight variations as the crackers are formed. At the installation of a cracker line, process rollers should be properly aligned to prevent weight variation, Mr. Green explained.
“Fundamentally, the accuracy of the equipment installation and the alignment of all process rollers need to be ensured to rule out this element should product weight variations occur anywhere during the forming process,” he said.
At high speeds, reduction ratios must be smaller to prevent too much load from being placed on individual rollers and ensure accuracy of the entire dough sheet.
“We recommend four reduction stations after the lamination process, including the finish gauge roll station,” Mr. Smith said. “In some cases, we recommend larger diameter rollers. We have found the larger diameter induces less stress in the dough sheet as the reduction process is performed.”
Spooner Vicars’ A-PEX400’s latest design uses 400-mm gauge rollers to minimize roller deflection and maximize consistency. The sheeter also incorporates servo technology to improve positional accuracy of the dough sheet.
Smooth product flow
Ensuring an even flow of dough throughout the process remains the biggest challenge for high-speed production, Mr. Smith said. Without it, processing can get out of control very quickly. This includes controlling the speed of the dough sheet through the gauge rollers and across transfers from one piece of equipment to the next.
Without control over the sheet as it flies through processing, the conveyors can over- or under-feed the gauge rollers. This results in inconsistent reductions and lost dough. To stay in control of the process through the sheeter, RBS employs a laser-based dough flow control system. Lasers at each gauge roll measure the height of the sheet as it approaches the roller and then automatically adjust the speed of the conveyor as needed to maintain the desired height, preventing over- or under-feeding.
Spooner Vicars also employs a laser to measure dough height as the dough sheet is reduced.
As dough moves through the line, transfer points become a risk to the smooth product flow that is so critical to efficient and fast production. Transfers are a place for the dough to get off-track and distorted. Much of this is addressed up front during line design and installation, Mr. Green explained.
“All conveyor transfer points need to be designed with adjustment and set optimally to ensure precise product transfer without distortion,” he said. “Auto-web tracking/guidance systems must be sensitive enough to ensure a quick response to match the higher conveyor speeds and ensure positional accuracy of the product between transfer points.”
Once the production line is set correctly, the latest control systems help operators keep the process moving.
“The modern technology in control systems and digital control systems allow operators to make adjustments in one location, and everything behind it will automatically adjust,” Mr. Parlour said. “In addition, we can develop centerlining guidelines that keep the line running within them.”
Not only are cascade controls critical, but Mr. Green said intuitive HMI displays also help operators make quick and efficient adjustments as production moves.
This article is an excerpt from the June 2019 issue of Baking & Snack. To read the entire feature on cracker technology, click here.