While designing a custom conveyor system Wrabacon was challenged to provide a reject system to reject under/overweight product from a high speed processing system. The product passed the check weigher at 220 FPM.
Our team of designers went to work and after testing several solutions the decision was to design and manufacture a stainless steel over-head servo controlled over-head reject system. Because the product was wet and the system was to be installed in an area where wash down would take place the reject system was designed entirely with wet duty and wash down components.
Due to the limited space where the reject system would be installed the over-head system was designed with paddles to sweep the product. This design choice saved space by eliminating side pneumatic cylinders which are typically used in reject systems. As product passes over the check weigher a signal is sent to the reject system should an overweight or under weight product be detected. Once the product enters the reject system a paddle that is attached to a rotating chain sweeps the product into a reject bin.
Our diverse experience in the industrial automation industry has prepared our team to identify and overcome a variety of challenges presented by our clients’ products, facilities and processes. Recently a national wet wipe manufacturer tasked us to develop an advanced handling system to integrate into their existing facility. This was an entirely new manufacturing line, custom designed to increase production to meet new orders and keep up with demand.
The first challenge the product posed was the nature of the product itself. Due to the wet, damp characteristics of the wet wipes prior to packaging, the entire handling system was designed and built with stainless steel conveyor components. The second challenge was accumulating wet wipes from the converter.
To ensure the handling system operated seamlessly, we teamed-up with a conveyor chain manufacturer to design custom chain that would allow accumulation of a wet product, or in this case, the wet wipes. This process took place in the low-pressure accumulation area noted in the system plans. At Wrabacon we welcome these challenges to keep our knowledge and skills ahead of the rest.
The Handling System and How It Works
Basic System Process
The basic process for the handling system is as follows. The wet wipes are produced from a converter and transported to an accumulation system which then feeds two existing high speed over wrapper packaging machines. If wipes are not sent to the over wrappers they are sent to a machine that places them into plastic containers. If the wipes are over wrapped the packages are sent via the 3-1 merge to either a hand pack line or a cartoner machine.
Detailed System Process
Stacks of wet wipes transfer through a check weigher in a single file. This effectively measures the weight of the product and indicates that each container has the correct moisture content. Product is then transferred onto a short reject conveyor equipped with an overhead sweep mechanism. This sweep mechanism is used to reject stacks of wipes from the line that could disrupt downstream elements of the handling system. The wet wipes are rejected based on a signal from the checkweigher.
After passing through the reject conveyor, the stacks enter a 5-lane tunnel style diverter. In normal operation, the stacks of wipes travel straight through the diverter, enter a merge system around a ninety-degree turn and onto the final diverter. During normal operation the stacks enter the final diverter and are equally distributed to the four downstream lanes. Based on a downstream signal, if a wrapper is not online, the diverter diverts the stacks evenly to the remaining wrappers. If accumulation is required, the first diverter diverts the wipes evenly to five low back pressure accumulation conveyors where the stacks accumulate.
Each conveyor is approximately 18’ long and holds 30 stacks of wipes (based on a 7” long product). After the accumulation section, the gate and release merge system releases lanes of the accumulated stacks to merge them back into one lane for the final divert when the need for accumulation goes away. The gate and release merge systems are located at the end of the low back pressure accumulation conveyor. The stacks merge to the center of the merge conveyor using two vertical side belts that help keep the stacks together. Both diverters are “tunnel” style and utilize servo motors for positioning.
After the second diverter, we designed and built a series of conveyors that take the stacks of wet wipes to the wrappers. Lane one feeds the closest wrapper, lanes 3 and 5 are the future wrapper lines. Lanes one and two travel around a ninety degree turn and then through to the corresponding wrappers. After the wrappers, the two lines merge into one and enter one of two downstream lines (ergo line or tray line). The tray line will consist of a dual pack off conveyor and a tray conveyor. The merge will be constructed wide enough to handle the future line three. Line four travels straight down to a thermoform line where the stacks are manually loaded into the thermoformer.
Handling System Specs
To improve the production system, Wrabacon designed and build the following product handling system components:
(1) Overhead sweep reject system
(1) 1:5 servo controlled diverter
(5) low back pressure accumulation conveyors
(1) gate and release 5:1 merge
(1) ninety-degree conveyor
(1) Line 1 conveyors including a ninety-degree wrapper infeed conveyor, a wrapper discharge conveyor
(1) Line 2 conveyors. 3:1 Merge to hand pack off
Production Rate: 225 wet wipes per minute. Product Size: 7 long x 4.25 wide.
No matter what industry you’re in – if you ever deal with automation, you understand that it has a lot of moving parts (and that’s not exactly a pun). The moving parts you find in an automation system run the gamut from feeders and conveyors, to diverters, stackers, and everything in-between. But what really matters are the “parts” that influence an automation system without ever actually being a part in it – like the space it exists in and the characteristics of the product it’s built to accommodate. For our team at Wrabacon, this is what makes the difference between simple automation and creative automation.
Consider for example the challenge posed by one customer in the glass converting industry.
With a fragile product in 4 different sizes, a small amount of space to work with and strict timing parameters to accommodate – creative automation is exactly what they needed.
Transfer four different size glass sheets from an existing screen printing machine to an existing oven infeed, allowing inks to cure on the glass sheeting.
What is a transfer system? A transfer system is a safe, reliable, efficient system that transfers products from one step in the process to the next with little to no human interaction.
The client produces screen prints on 4 different sizes of glass sheeting. The entire process took place in a 16 x 15-foot production area.
Before creative automation, the process was slow, unpredictable, and antiquated. It required 2 employees to maintain glass alignment on the system and the need to maintain the proper gap between the sheets prior to the transfer of the sheets into the curing oven. It also relied on outdated parts, software, and controls that prevented the business from scaling with demand.
Wrabacon’s task was to introduce a more modern, efficient, and effective system that improves efficiency and control, while operating within the existing room layout, with less manpower.
How the Glass Transfer System Works
Step 1: The glass sheets exit the screen printing machine single file and transfer onto a 90-degree rotating conveyor.
Step 2: The sheets transfer downstream on conveyor 2 to the pop up transfer zone.
Step 3: The glass sheets enter the pop up zone which is made up of conveyors 3, 4 and 5. There are two pop up sections, one for each glass sheet. The first sheet travels over the first pop up zone to the second zone. When sensed, the pop up extends upward, lifting the sheet off the rollers.
Step 4: The next sheet enters the first pop up zone and when sensed, is lifted off the rollers.
Step 5: When both sheets are positioned, the conveyor belts start and transfer the sheets side by side onto conveyor 6. This conveyor brings the sheets to the oven infeed where they are transferred for downstream processing. The area where the transfer occurs has an approximate temperature of 80 degrees Fahrenheit.
Step 6: We connected conveyor 6 to the existing oven variable speed drive. Using a 0 – 10 VDC signal, conveyor 6 follows the linear belt speed of the oven to allow for the proper gap between the trailing edge of the first sheet of glass and the leading edge of the second sheet of glass.
The resulting system for our client was a completely custom solution, that allows the customer to complete one full sheet in 18 seconds. This has allowed the customer to drastically increase their output, provide more accurate lead-times, and grow at a faster rate.
Have questions about how creative automation can make a difference for your business or industry? Wrabacon is the authority.