The Toughest Roles to Fill
Filling-equipment providers devise some pretty creative solutions.
Gel-filled pens required a boat-like mechanism from National Instrument to hold them in place.
Putting tablets in a bottle or liquid in a vial isn’t always a simple order to fill. From dusty and crumbly tablets, to expensive and delicate biopharma liquids, to tubes with uneven bottoms, manufacturers of filling equipment are continually presented with customer challenges. With a mix of technology, creativity, and determination, here’s how several companies managed to get the product in the package.
A TRICKY TABLET
NJM/CLI (Lebanon, NH) helped Leiner Health Products (Fort Mill, SC) meet production-speed goals filling a 2-mm flat antacid tablet. “It causes problems because it breaks very easily,” explains NJM/CLI vice president of sales Mark LaRoche. He adds that the tablets tend to stick together and are almost as wide as the mouth of the bottle. “That makes it difficult to put the tablet in the bottle with any speed,” he says. With a slat counter, the customer had experienced excessive product breakage. Use of an electronic counter would solve the breakage problem, but fell short of the 100 bottles per minute speed requirement.
The solution was a Cremer CF1220D electronic tablet counter. Creating a special V on the middle plate on the vibration tray and a cutout on the front plate prevented stacking and leaned all tablets to the same side. A customized funnel allowed tablets to easily enter the bottles. Accomplishing the modification with change parts was an added bonus. “The customer already had electronic counters, and he liked the idea of the flexibility,” says LaRoche.
To fill a soft and dusty Class II solid-dose tablet, Aylward Enterprises Inc. (New Bern, NC) had to start with some cleanup. “The challenge was to very precisely count this product and to get rid of the dust and broken product,” says Matt Neumann, vice president of sales and marketing. Aylward removed broken tablets and dust using a custom in-line screening process during bulk transfer.
With no dust to cover the lenses of its LED product scanners and fewer broken tablets to slow it down, the company’s ACT 815DL filler could inspect and fill the product to Class II standards at speeds of 150 to 200 bottles per minute. The machine uses a patented feed wheel rather than vibrating-tray technology. “We’re separating the tablets mechanically and filling one bottle with one wheel,” Neumann says. Each tablet is scanned and counted in free fall just before it enters the bottle. If the scanner detects a broken tablet, the feed wheel stops immediately and that bottle is rejected. As an additional feature, Aylward is now offering a model with complete product containment.
WEIGHING IN TWICE
An insulin product that required filling of two separate liquids into each glass vial—and checkweighing each part of the filling—was a challenge for a Bosch Packaging Technology (Minneapolis) customer. The traditional approach would involve pairing two filling machines with checkweighing, explains Jeff Jackson, director of product management and marketing for the company’s North American Pharmaceutical Division, “but the machines get very large, and it becomes a custom machine.” Instead, Bosch employed its 16-head FLM filler with checkweighing, which did the job with a single standard machine that fit the customer’s existing facility.
“Instead of configuring the machine as a 16-head filler, we configured it as two 8-head fillers,” says Jackson. “It’s just a sequence that we customized.” The checkweigher works parallel to the filling operation, pulling sets of eight vials for weighing prior to filling and after each fill. Pulling sets of vials rather than single vials increases the sampling rate from 1–2% to 3–4%. “The customer looked at it and said there was nothing else,” says Jackson, “because everyone else was proposing two machines.”
Customers of Optima Machinery Corp. (Green Bay, WI) aren’t just looking for ways to handle filling of challenging products. They are also looking for flexibility, according to Eric Knight, East Coast sales manager of the company’s pharma group. “In some cases where the range of products is quite diverse, we have designed solutions with multiple dosing units on the same provision,” says Knight. “The platform is standardized in the facility. By means of changeover, the equipment can handle specific production filling with systems that are more suitable for those products.” Optima offers a range of closure-insertion methods.
The company has also helped clients evaluate dosing and handling methods most appropriate for their products. This evaluation goes beyond obvious issues of materials compatibility to look thoroughly at the product itself. “For example, it is important to understand whether the product is oxygen sensitive,” says Knight, “whether the product matrix includes the need for gas purging during the filling or closing operations, or whether there are specific conditions to be maintained during the filling process overall, such as maintaining a cold product or a suspension product.”
UNEVEN ON THE BOTTOM
In filling a tooth-whitener product into a gel-filled-pen application, National Instrument Co. (Baltimore) faced a trim, uneven container shape that was difficult to position for consistent fills. “We accomplished this by engineering an MRV eight-head system with spool-type piston valves that could handle the thick consistency of the gel product,” says sales and marketing coordinator Mary Burchard. “The pens were fed by elevators into vibratory bowls that oriented them for consistent placement into a boat mechanism.” This boat held the pens upright, and nozzles were inserted deep into each pen and withdrawn slowly with the fill.
Filled pens were conveyed to a servo-driven pick-and-place mechanism that placed push-on brush-and-cap assemblies. Chucks applied a downward force to seat the assemblies on the pen bodies, while the boats were lifted slightly to aid in the capping. “Our Filamatic equipment was able to help a supplier of a new product beat much of his competition to market,” says Burchard.
NO HASTE, BUT NO WASTE
When a product costs thousands of dollars per vial, avoiding waste becomes more important than speed. This was the case for an M&O Perry (Corona, CA) customer with a bio-pharma product involving both powder and liquid filled into glass vials. Tolerances had to be tightened to ±0.5% for the liquid fills, and ±2% for the powder. “They’re tight requirements,” says sales manager Matthew Gingerella. “We had to integrate some advanced features to make sure that accuracy is maintained throughout the run.”
Also, 100% checkweigh systems for both powder and liquid filling included automatic feedback loops to continuously adjust the pump and powder ports. Servo-driven custom-made piston pumps allowed precise control. Line speed was 20 vials per minute.
The machine’s touch panel was upgraded to show the checkweigh readings, and a printer was integrated to print checkweigh data line by line in real time. The printing system is backed up with a flash memory card, and the entire data collection system is backed up by an uninterruptible power supply.
IMA Nova Packaging Systems (Leominster, MA) has been presented with a number of extremely dusty tablet products in recent years, according to vice president and general manager Stewart Harvey. Dust buildup from these tablets poses a problem for the infrared sensors on traditional electronic counters. “You can run them on the machine for 10 minutes, and then the machine basically can’t see,” Harvey says.
For handling of these products, the company introduced EFS (Electronic Field Sensing) as an option on its electronic counters about five years ago. The sensors employ 32 electrodes that flood the sensing field 4000 times per second. “When a product falls through, it causes a disturbance in the field,” explains Harvey. “That disturbance is roughly equal to the mass of that product.”
The sensors can be used even with very dusty products, and they can detect broken tablets and accurately count tablets that stick together. This technology, Harvey stresses, is just one option in IMA Nova’s range. The company is currently introducing a new counter that looks at the product with video cameras and can individually reject tablets even before they enter the bottle.
A TOUGH-TO-FILL TUBE
In building a squeeze-tube filler for a pharmaceutical customer packaging a sterilizing powder, Prosys (Webb City, MO) had to bring together nonstandard filling and standard sealing in one machine. “It required us to remove the standard fill station (a volumetric piston filler for gels and creams) and to integrate the physical and control elements of a nonstandard assembly into a standard machine,” says sales manager Gary T. Lowden. The other challenge was in dealing with the powder. “If any of the powder material contacted the area of the tube that needed to be sealed, the seal would not hold,” Lowden says.
Prosys was able to successfully modify a standard RT 60 model, integrate an auger fill head, deal with the dust issue, and provide what the customer was looking for. “Regulations and product usage methods required the product to be in a squeezable tube,” says Lowden. They were also looking to differentiate themselves as well, and wanted to stay away from traditional containers. “Our competitive advantage,” says Lowden, “was that we were willing to listen and spend the time and energy to come up with a solution.”
PRECISE FILLING IN AN EXPLOSIVE APPLICATION
Servomotors are now often tapped to drive filling systems, given their precise control over nozzle-head movement and dispensing speeds. But when ESS Technologies Inc. (Blacksburg, VA) was charged with designing a filling system for a product running in an explosion proof enviroment, the filling system designer had to find another solution for precise filling. ESS Technologies offers filler-cappers that can handle a variety of liquids and powders. It starts with a common platform then customizes the feeding and dispensing systems as well as capping and insertion stations.
“No standard servomotors, PLCs, or electrical fixtures could be within 10–20 feet of the filler,” explains Walter Langosch, sales and marketing director. Kevin Browne, president and chief engineer, started with the company’s base machine, then designed a mechanical solution using cams to guide a precision-volumetric syringe pump. ESS achieved an accuracy of ± 0.15 g. “We worked closely with Mettler Toledo Hi-Speed Checkweighing Div. to tailor its system to the application,” says Browne.
ESS mounted Mettler Toledo’s weigh cells onto a vibration-dampening pedestal within the system, adding its own proprietary engineering. High-precision spiral-bevel gearboxes allowed ESS to drive the syringe pump with zero backlash from intial stroke to discharge stroke, says Browne.
Langosch adds that given the customer’s need for extreme precision, ESS weighed all glass vials before filling and immediately after. “Glass can vary in weight, so we needed to weigh every vial to deliver the tolerances requested,” he says.
ESS also designed a remote electrical cabinet 20 ft away with all wiring held behind intrinsically safe barriers. An explosionproof cabinet could have been employed and used alongside the filler, but Browne says the remote cabinet was more cost-effective.