While we’ve built our business and our reputation on the strength of our lab glassware, we at DWK Life Sciences know the important role that lab tools and accessories play in your success. That’s why we’ve assembled a wide selection of precision tools to help ensure the accuracy and repeatability of your results. From staining dishes to crimpers, dispensers to stopcocks, we’ve got you covered. We put just as much thought and innovation into these lab basics as we do into our industry-leading glass components. That’s why our bottle-top dispensers combine the latest in dosing technology and comply fully with current safety regulations. It’s why our tissue grinders are available in both reusable and disposable plastic, sterile and non-sterile versions. And it’s why many of our lab tools have replacement parts available — an innovation in lab economics.
Frequently Asked Questions
Although it is possible to convert your crimper by replacing the internal crimping jaws and plunger, it is not advisable. Manufacturing uses special fixtures to help assemble the components.
There is a special crimping head for aluminum seals with the plastic closures that is often termed a flip-off crimping head. Please make certain your crimping head has the jaws with the internal recess for the plastic button that is part of the seal.
The easiest way would be to measure the diameter of the plunger. The plunger is approximately the same diameter as the seal and contacts the top of the aluminum seal during a crimping operation.
Usually, the indentations are is caused by over-tightening. We suggest that you try adjusting the crimping tool for a looser seal.
Crimp closures are generally well known for their excellent sealing characteristics — an absolute must maintain parenteral content integrity and long-term sample storage. It has to be noted, however, that the quality of a crimp seal is strongly dependent on the right calibration of the crimping tool used to apply the closure to the vial. To maintain good results, make sure to re-calibrate your crimping tool regularly and check the quality of the seal every time you crimp. The best way to know if your vial has been crimped properly is to visually inspect the overall appearance of the crimp.
An optimal crimp result is characterized by the following features:
- The cap surface is flat.
- The sides of the cap fit tightly around the vial neck and do not show any deformations.
- The septa is not being sucked into the vial nor does it emerge out of the center hole.
Many of our customers rely on the so-called “turning test” or “twist test” to verify the crimp result. To test the quality of the crimp, the vial is held in one hand while the other hand is used to test whether the crimped cap can be turned or not. A cap which does not turn indicates a good crimp.
Warning: this test is not very meaningful for two reasons:
- Many septa come with a PTFE lamination. Due to the smooth surface of the PTFE membrane, the cap can be turned even if the cap was crimped correctly.
- An over crimped closure which passes the turning test will have impaired sealing characteristics due to the deformation of the cap and septa.