Advances in Automated Manufacturing Equipment
Specialist Automated Machinery for Handling High Volume Pipette Tips and Reaction Vessels:
German manufacturer of robotics Waldorf Technik has recognised the importance of automated high volume injection moulding systems, especially pipette tip manufacturing, by developing a dedicated automation machinery concept, Vario Tip. The concept is outlined in detail in a paper which is available from the editor at sam.a@rapidnews.com.
The paper recognises key technical challenges faced by manufacturers and outlines how its Vario Tip concept solves these challenges. In particular, it outlines how to achieve high specification quality requirements while ensuring optimum levels of productivity for what it describes as “massive” volumes.
The paper summarises the challenges involved as follows. First, there are the challenges related to the specifications of the part itself with regard to dimensions, straightness and surface defects. Secondly, there are challenges with the handling and packaging which often demands traceability down to the cavity level. There is also a challenge with the operating environment to ensure contamination-free production which then brings with it a battery of GMP standards. Last and certainly not least is the sheer volume associated with modern production concept, having short cycle times and as many as 32, 64 or even more cavities. The sum of all of these factors adds a degree of difficulty which only an efficient and reliable automation system can overcome.
It then goes on to say how its Vario Tip concept, which has been internationally patented, can be used to develop a solution to these challenges. The process begins with getting a definition of the process—in other words, establishing a clear picture of the needs of a new robotics system—understanding the cost of quality, the environment, and productivity and efficiency.
Once this has been framed, the solution can be tapered to a manufacturer’s needs. This involves understanding the capabilities and technical specifications of Waldorf’s robots. The description, according to the paper, is that this involves “high speed, precision take-out devices to remove parts from the mould with a minimum of encroachment on the mould open time. Extremely dynamic acceleration and deceleration is made possible through the use of lightweight yet stable alloy and composite materials. In many cases, the dynamic motion allows a certain amount of overlap of the mould and robot motion to safely minimise the mould open time.”
The paper goes on to say: “The configuration and features of the cell are very much application specific and while many pipette solutions share some common attributes, each system is custom tailored to the customer’s needs for product mix, secondary operations, handling and packaging needs and labelling.”
It also makes mention of cleanroom compatibility and consideration of the production cell’s footprint. Cleanroom compatibility means paying attention to the details which contribute to contamination so that no particulates are expelled into the atmosphere. It also means fully contained use of air or elimination of air usage altogether. Equally important is ensuring low noise emissions to enhance the work area. Most of the high performance drives incorporate water cooled servo motors and linear drives to reduce the radiant heat expelled into the machine room. After all, heat dumped in the cleanroom is only removed with expensive air conditioning and water cooled heat exchangers are much more efficient and operate at a fraction of the cost.
The Vario Tip concept allows for a vision inspection system to check, reject and even replace with like cavity numbers if desired; all before population of the racks so that only top quality parts are placed in the rack for processing.
The concept can be adapted to include the packaging of the rack into the so called “selling unit packages”. This may include everything from “bulk pack” to multi-tier racks in a blister pack with customised foil sealing. Waldorf Technik say their technical solutions to these requirements are as many and varied as the customers who use them.
Maximising Yields on Automated Dispensing Lines
Dispensing equipment manufacturer Nordsen EFD has kindly provided the following information about how to maximise yields on automated dispensing lines.
Adhesives, lubricants and other assembly fluids are used to build a wide variety of medical devices. On automated production lines, these materials are often applied with pneumatic dispense valves.
Although dispense valves may be a small part of the overall assembly line, choosing the valve that is most appropriate for a specific application can significantly increase yields while reducing the number of rejects and while cutting assembly costs. Valve integration can be streamlined and production lines kept running at maximum efficiency both by carefully matching the valve to both the application and the fluid being applied, and by using a dedicated valve controller to simplify setup and operation.
Matching the valve to the application: Although it is possible to achieve similar results with different valves, some designs will perform better than others in specific applications. A diaphragm valve, for example, is a good choice for UV-cure adhesives because this design will minimise turbulence which could produce bubbles in the fluid. There are no seals to wear out and leak, and the fast, clean cut-off will eliminate drips that could cause functional or cosmetic damage to parts. For reactive fluids like cyanoacrylate or “super glue,” the same diaphragm design with wetted parts made of an inert ultra high molecular weight polymer will keep fluid from curing inside the valve.
When making very small deposits or dispensing watery fluids like solvents, a needle valve is typically recommended. Because the needle seats in the tip adapter, there is virtually no dead fluid volume remaining between shots. A well-designed needle valve with self-adjusting packings to compensate for wear can provide tens of millions of trouble-free cycles before maintenance is required.
For thicker fluids and filling applications, a piston valve with an adjustable flow control will provide good results. The piston design produces a faster flow rate than diaphragm and needle valves, and a snuffback action as the valve closes will prevent fluid from dripping or oozing between cycles.
These are just three general-purpose designs. Other configurations include precision spray valves for critical coating applications, aseptic valves for dispensing sterile fluids, and piezoelectric valves capable of speeds as fast as 500 cycles per second.
Valve controllers maximise accuracy and efficiency: Once the valve has been selected, the most effective way to integrate it into the assembly line is with a dedicated valve controller.
Pneumatic dispense valves use a combination of fluid pressure, valve open time, and tip size to determine the amount of fluid applied. Higher pressures, longer open times and a larger tip will produce larger deposits; lower pressures, shorter times and smaller tips will result in smaller deposits. Once initial setup has been completed, valve open time can be adjusted in increments as small as 0.001 s to finely tune the size of the fluid deposit.
Manufacturing personnel sometimes ask why a dedicated valve controller is recommended, when they could actuate the valve by indexing or other mechanical means, or by linking it to an existing programmable logic controller (PLC). The simplest explanation is that a dedicated controller is the easiest, most accurate way to adjust valve open time, and it puts this capability right at the dispensing station. By supplementing—rather than replacing—a PLC, a valve controller can provide several important benefits.
Instron Machine Simulates Spring in Automated Testing of Auto Injector Prototypes:
US-headquartered testing equipment manufacturer Instron has developed a dynamic test method which replicates an auto injector spring—the ElectroPuls. The company has stated that the technology will be useful for designers as it offers them a way around the problem of having to iteratively test large numbers of springs when developing new auto injector device designs. As a result, the development is expected to save significant time and reduce a perceived level of tedium traditionally involved with auto-injector pen design.
Factors such as drug viscosity, needle diameter and the type of lubricant used all play a role in determining the rate of drug delivery, which is the key variable of interest. Different springs can be simulated and the effects analysed using Instron’s machine, along with the appropriate control software.
Instron have developed this application in response to the trend for more and more patients being treated at-home. With this, medical device companies are catering to an increasing demand for safer, more user-friendly biomedical solutions.
According to Instron, the company’s recommended control software is clever enough to handle complex problems related to the idea that any tests need to take into account the fact that the machine is simulating a spring where the applied load and injection time are key variables.
Instron solves this control challenge using Modal Control, an advanced feature of the 8800 controller which creates a “composite” channel to allow the applied load to vary with actuator position. The user needs to specify the initial preload and spring stiffness in order for the system to adjust itself based on the actual load seen by the syringe. The resultant load and system displacement data is acquired by the 8800 controller at a rate of up to 5 kHz. A force vs time graph is produced and dispensing time and stall force of the syringe is calculated. The user can then determine if the chosen parameters for spring stiffness and preload have yielded an ideal auto-injector dispensing time for a given drug.
Zwick’s Automated Testing of Finished Auto Injectors
German testing equipment manufacturer Zwick has written about its equipment for the automated testing of finished auto injectors for quality control applications. The prime considerations when testing these products are reproducibility of results and reduction of operator influence. The standards relating to quality assurance tests on insulin pens and carpules are EN ISO 11608 Parts 1 to 3.
Zwick’s system is based on a Zwicki-Line Z0.5 TN table top testing machine with additional torsion drive. This allows the various operations of the pen to be tested using a single device. The testing machine measures the dosage setting, injection force, stroke and plunger-rod thrust in one continuous process. Test methods on the two test axes can be modified and combined as required. If tests are to be performed with a cartridge installed, an optional laboratory scale option which measures the insulin dose delivered can be fitted.
Automated specimen feed can be achieved using Zwick’s roboTest R handling system (see image in middle column) plus autoEdition2 automation software. The pens are fed into the testing machine from the magazine (capacity up to 50 specimens) and the test is started. Variation in test results caused by operator influence is eliminated and specimen throughput increased, making the test significantly more efficient. Testing can, however, be performed manually at any time if required.
When used in combination with Zwick’s testXpert II testing software, the system is able to fulfill FDA requirements on electronic records and electronic signatures stipulated in title 21 CFR Part 11 of the code of federal regulations.
Automated Camera Controlled Pipetting of Fluids During Assembly
US manufacturer of manufacturing robots Epson has published a case study illustrating how its Scara robots have been used for the automatic pipetting of droplets of fluids during the manufacture of cartridges for in-vitro diagnostics in a cleanroom.
The robots have been used by Xenon based in Dresden, Germany, which makes automation equipment for assembly, testing and automated packaging. Xenon have built a camera-controlled automated pipetting system for the manufacturer of the cartridges with a footprint of just one square metre.
During automated pipetting of substances, Epson says that a dosing needle must be positioned accurately, even if the target cannot yet be defined exactly. In addition, it must be possible to implement such a task effectively and affordably.
According to the case study, Epson’s Scara cleanroom robot carries a mobile camera that can inspect the different areas and makes it possible to correct positions. Even if the target part is not always positioned in exactly the same place, the camera work makes it possible to move to dosing or gripping positions accurately. A second camera carries out quality controls. It checks whether the filled drop is in the correct position and has the required size.
Input and output of the capillaries are flexible. The Epson Scara robot puts the filled capillaries on a sample carrier, installs them in a disposable cartridge or deposits them for shock freezing into an integrated Dewar vessel in liquid nitrogen. Handling, dispensing and QC functions of the pipetting platform can be combined with each other and programmed in various sequences, which makes it possible to adjust to new tasks and products at any time.
For the production of such medical products, it is important that relevant batch-related data, like for example the capillary diameter or drop size and the appertaining camera images can be recorded and archived.
Fipa’s Sprue Gripper “Senses” Low Tolerance Sprue Positions
German manufacturer of end of arm tooling Fipa is offering customers a new sprue gripper, the GR04.101A. According to the company’s CEO, Rainer Mehrer, a key feature of the gripper is its large sensor area for improved sprue detection and control, which allows the gripper to adapt to low tolerance sprue positions, regardless of the position of the sprue in the mould.
The gripper exhibits a strong gripping force, 22 N, to encourage a secure grip at fast cycle times. It is coated with a robust Hartcoat treatment which gives a long cycle life and high wear resistance. Thanks to its compact construction, low weight and large jaw opening, Fipa says the new gripper can easily be integrated with existing Fipa gripper modules.