Build laboratory equipment “clean…save…installation space”

Ulf Hottung | 8. October 2019

Many requirements are clearly defined for the development of a laboratory instrument. Anyone who wants to build or optimise laboratory equipment or offer new laboratory technology is always faced with the same task.

The new device must offer at least the following, regardless of the task it is to perform:

  • Reliability
  • Productivity
  • Reproducible and documentable results
  • Take up as little space as possible
  • and ideally offer an ROI (return of investment) in the very short term

In this blog post we demonstrate how igus products “clean…save…installation space” through their respective specifications. E.g. through small bend radii, installation possibilities in punched plates or the availability of individual designs.

Background to the requirements

The device is intended to perform a recurring and time-consuming standard process in the laboratory, which up to now has mostly been done by hand. Even at medium production rates, the system is profitable and increases laboratory capacity utilisation.

Innocyte Split-It , laboratory device with more than 30 igus components per device

Routine work: “Cell passage”

Due to the steadily increasing demand for adherent animal and human cell cultures in biology, medicine, pharmacy, immunology, virology and many other disciplines, the “passage” plays an important role in their provision.

Here, microorganisms or viruses are often transferred to culture media or other cell cultures in order to maintain them or detect changes in the new environment.

Substrate is drawn from the mother bottle and distributed to daughter vessels. A rather tedious manual task.

Optimised function in the smallest space

igus energy chain and chainflex cable in laboratory equipment in a very confined space
Installation position of energy chain and cable on plate-bearing of mother bottle

Space in the laboratory is extremely limited and valuable. Solutions must be space-saving, which means that particular aspects must be taken into account.

The mother bottle must be moved and thermally controlled in the device. The height of the intake can also be adjusted for different bottle formats. Here an E2 micro type energy chain and a chainflex cable of type CF98 with a bend radius of only 4xd undertake the sensor and power supply.

chainflex cf98 in endurance test with bend radius 4xdiameter
chainflex CF98 cable in endurance test with 4xD

More details about the test results can be found in this link: https://www.igus.eu/info/unharnessed-cables-tested-cf98?L=en

Even more important than costs and installation space: hygiene

It goes without saying that contamination of any kind must be excluded. After replication, the substrates are subjected to toxicology and side effect tests, among others. And also examinations for tumour and drug research.

The passage often takes less than 30 minutes, despite exposure and rest periods.

The device must then be cleaned and prepared for the next cycle. For this purpose the fluid circuit and the mechanics were strictly separated. The fluid lines can be rinsed sterile, the mechanics do not require any maintenance.

Avoid all contamination

With minor exceptions, the mechanics consist of maintenance-free and lubrication-free igus components, which perform their service without additional lubricants.

Plain bearing without lubricant and sectional view of the bearing wall
iglidur plain bearings sectional view and installation condition

These elements are grease-free on their surface and therefore neither can anything adhere to them nor can any lubricant escape.

The test according to DIN EN ISO 846 method A, carried out on various iglidur materials, also shows no mould formation and no material changes could be detected.

How this works and more about the structure of the igus tribo-plastics can be found here: https://www.igus.eu/info/plain-bearings-iglidur-features?L=en

Added value: desired contour

The guidance of the needle which is necessary to perforate the bottle cap also had to be redeveloped. Due to the large stroke, the spring of the hold-down device lay against the needle guide. Signs of friction and, in some cases, signs of wear were visible on the guide rod.

Spring with support disc to avoid buckling and abrasion
Spring guide with plain bearing spring support

The spring was split in two and a spring disc with integrated iglidur plain bearing now performs the stroke movement.

For information go to: https://www.igus.eu/info/customized-components?L=en

Special bearings by machining, 3D printing or moulding tool
Customised plain bearings

Now the spring guide is just as wear-resistant as the lifting device of the mother bottle arranged next to it. A drylin AWMP, aluminium precision shaft in combination with an iglidur J plain bearing is installed here to minimise wear. This regularly results in the lowest wear in the igus laboratory.

Consistently keeping an eye on costs – mechanical engineering in sheet metal

A special sophistication of the drive function is the cam disc design, a parallel-mounted drylin T profiled rail guide performs the lifting movement of the bottle plate and can be individually adjusted to the manufacturing tolerances of the device frame, which is mainly made of sheet metal components.

Crank drive transmission of movement through drylin T profiled rail guide
Cam disc – motion transmission with drylin T profiled rail guide

In the list of requirements at the beginning of this article I have referred to the ROI. The sheet metal construction plays a major role here.

Regularly, sheet metal structures are considerably cheaper than structures milled or made from profiles.

However, this only applies if the quantities are correct and special features such as distortion due to punching and bending processes and differences in height due to tolerances are taken into account.

For good reason, the device contains considerably more than 20 igus components for flaps, mechanisms, feed-throughs, etc., which are either specially designed for use “in sheet metal”, such as the iglidur clip bearings, or simply offer significant design advantages, such as misalignment compensating igubal spherical bearings, which are available as one-clip, two and four-hole flange bearings for screw mounting.

More about igus solutions for sheet metal here:

iglidur clip bearing: https://www.igus.eu/product/236 iglidur fixed flange bearing: https://www.igus.eu/product/213 igubal clip bearing: https://www.igus.eu/product/393 igubal fixed flange bearing: https://www.igus.eu/product/381

The form and functionality of the components were adapted to sheet metal, the properties of the iglidur materials used remain the same.

Summarised

The “simplification of the laboratory routine”, designed from the outset for optimum applicability and fast amortisation, can be successfully achieved by using appropriate components.

Particularly the design points lying in the mechanical construction: Installation space, “saving” and hygiene can be accomplished convincingly and economically with tribo-polymers.

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