Precise room linear robot for customised filling system in bioanalysis

• What was needed: drylin® E-room linear robot, consisting of drylin® ZLW-0630 toothed belt axes with motor and a drylin® GRQ rack and pinion axis, NEMA stepper motor, chainflex® motor cable and plastic-energy chain of type E2
• Requirements: Compact system size with high effective usable area; strict chemical, hygiene and high purity requirements prohibit lubrication of the system; high robustness, simple operation and high precision; cost-effectiveness
• Industry: Medical technology
• Success for the customer: A robust, compact, quiet-running and reliable system was developed. economical solution. The modularity of the room linear robot also allows flexible adaptation to the size specifications.

The highly specialised Berlin-based company M2-Automation develops and builds devices for the production of diagnostic systems and sample preparation with very low dispensing volumes. The customised systems are used worldwide for the complex handling of liquids. They are used for medical research and environmental analysis, for example for medical microdispensing systems for the accurate, contact-free dispensing of chemical and biological liquids and suspensions in the picolitre and nanolitre range.

For the construction of a customised filling system in the field of bioanalysis and medical technology, a flexible solution for the automatic filling of different filling volumes from 0.05 ml to 500 ml into different vessels was to be realised.
A room linear robot was to be built for the filling system to optimise the ratio of effective usable space to absolute system size, as space in the laboratory is generally very expensive. The external dimensions of the system are 1,600 x 1,900 x 800 mm, while the available working area is 1,105 x 525 mm.

In addition, systems and equipment in the laboratory environment are generally subject to strict chemical, hygiene and high cleanliness requirements, which the gantry must also fulfil. Dirt and dust have no place in the laboratory. For this reason, the use of lubricants in the portal would also have been a clear exclusion criterion. The system also needed to be maintenance-free and therefore as user-friendly as possible.
Further requirements for the room linear robot were a high level of robustness, simple operation and the highest possible accuracy in order to be able to carry out the dosing process for different volumes and viscosities at an appropriate speed in a reproducible manner.

Finally, the responsible designer at M2-Automation also paid attention to the lowest possible weight, a compact type that should nevertheless cover a relatively large working area and the cost-effectiveness of the new design.

When designing the customised filling system, the responsible designer opted for a lubricant-free and maintenance-free drylin® E-room linear robot. Several linear axes are combined in the gantries to realise a multidimensional movement. As all moving parts of the axis are equipped with polymer plain bearings, the linear axes work without lubrication. For this reason, the systems are also used in other liquid handling systems in laboratory technology.

The ready-to-connect portals contain pre-assembled drylin® linear modules or drylin® linear axes with NEMA stepper motor.
Two robust, horizontally installed drylin® ZLW-0630 toothed belt axes with motor are used as x-axes. These are particularly suitable for positioning tasks where space is limited. The clearance height is just 31 mm with a stroke length of 1,100 mm. The axis length was customised to meet the requirements of M2-Automation. Two 600 mm long, mechanically coupled parallel axes, also of installation size ZLW-0630, are used for the y-direction. And a drylin® GRQ rack and pinion axis has been selected as the z-axis for the dispensing module. The stroke of 240 mm can be scaled at any time if required. In addition, the drylin® GRQ-axis has been equipped with a variably clampable holder for triggering the integrated proximity switch. This allows the exact release position to be set and changed quickly, increasing precision.

Overall, the modularity of the room linear robot allows flexible customisation to the size specifications. It also fulfils all requirements for positioning accuracy, speed and durability in the application. The price-performance ratio of the linear modules was also a decisive factor for M2-Automation. The positioning accuracy of the gantry is +/- one millimetre. Currently, up to 1,400 bottles can be filled in one system cycle. The axis system positions the filling needle precisely in each bottle neck. The maximum travelling speed is 300 m/s.

NEMA 11, 17 and 23 stepper motors with optical incremental encoders are used in a closed control loop. Inductive precision proximity switches have been selected as limit switches. In addition, chainflex® motor cables and our compact E2 series e-chain® complete the project. The energy chains protect the cables from wear.