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3D printed bevel gear drive for medication dispensers

Cost effective manufacture of a complex drive unit for a medicine dispenser

Profile

What was needed: a complex bevel gear and a drive element in the separating unit
Manufacturing process: selective laser sintering
Requirements: small installation space, maintenance-free, running performance of over 5 years
Material: iglidur® i3
Industry: Medical industry
Success through collaboration: Complex components manufactured quickly and cost-effectively, high service life, customised and simple arrangement of the components in the installation space

The dispenser reliably dispenses individually blistered medications at the pre-programmed time.

The application at a glance

JDM Innovation GmbH required a drive assembly consisting of a bevel gear and linear drive for the separating unit in a dispenser for personally packaged medication. The dosing unit was to dispense individual medicine bags according to a previously programmed medication plan. This required reliable and maintenance-free components that would fit into the very small installation space and provide more than 5 years of running performance. However, the developers did not get very far with standard injection-moulded gears. These meant time-consuming one-off assembly and therefore stood in the way of series production of the dosing unit. The problem was solved with the 3D printing service from igus®. The complex bevel gear and linear drive required were developed as a CAD design according to the individual requirements in the installation space. The parts were then manufactured using selective laser sintering and could be installed immediately. In addition to the individual, complex geometry of the parts, the igus® plastic iglidur® i3 was used to fulfil the requirement for a long service life. To date, the separating units and gears have been installed in around 400 devices that dispense medication up to 5 times a day. The components successfully passed the endurance test of 25,000 cuts carried out in advance.

With iglidur® i3 to the durable wear-resistant part

Thanks to the integrated solid lubricants, iglidur® i3 is maintenance- and lubrication-free, which is particularly advantageous for applications in which good hygienic conditions play a major role. In addition to the hygienic aspect, components made of iglidur® i3 are suitable for all applications with wear. The tests from igus' own laboratory® confirm an abrasion resistance that is 3 to 30 times better than that of conventional materials for laser sintering. The components also have a very high mechanical strength and are therefore particularly suitable for the production of spur gears, bevel gears, drive nuts, special sliders and spherical bearings. This was confirmed in a gear test. The spur gears made of iglidur® i3 had a service life 5 times longer than POM-milled plastic gears.

As a 3D printing gear expert, igus® offers various online tools for the configuration of customised gears. The service life calculator shows a realistic indication of the service life of your gear, based on tests carried out in the igus® test laboratory. In the configurator for gear and gear rack, the components can be easily designed according to individual requirements. In the online calculation, you immediately receive the exact unit price for your component.

Further information about iglidur® i3

The drive unit made of iglidur i3 successfully passed JDM Innovation GmbH's tests.

Problem

The limited installation space in the dispenser made it difficult to optimise the arrangement of the components. The installation of the drive unit was so complicated that it could not simply be solved with standard injection moulding gears. The transport belt of the cutting blade had to be kept under tension, which would damage the drive shaft of the electric motor, which is why the arrangement of the drive elements was different than usual. Installing standard gears would have led to compromises on the components and complex one-off assembly work. However, the dispenser was to go into series production. In addition, the components had to deliver a running performance of over 5 years.

Solution

The design freedom of additive manufacturing allowed adapting the components precisely to the requirements of the small installation space. The parts produced from the iglidur i3 SLS powder with selective laser sintering were installed and tested directly. The iglidur i3 SLS powder was developed specifically for laser sintering and has very good tribological properties. This allows component service life expectancy to be up to 30 times that of components made of conventional plastic. Parts could also be produced much faster than would have been the case with injection moulding. The delivery time is usually two to three days - for urgent projects, igus can also ship components within 24 hours.

Complex geometries printed simply and in a very short time

The bevel gear assembly in the separating unit of the dispenser was subject to various requirements, including a small installation space. A belt moves a roller blade that has a drylin® N miniature guide as a linear guide. The 3D-printed shaft is guided in two igus® bushes in the sheet metal. The use of standard gearwheels would have led to compromises in the installation space and complex one-off assemblies. However, series production of the dispenser was planned, which is why a more sensible alternative was sought. The company found a suitable solution to the problem with additive manufacturing. The customised CAD design of the bevel gear could be easily implemented using selective laser sintering. This meant that the drive unit could be fitted into the dispenser's small installation space without any compromises. In addition to the exact and detailed fit of the components, the durability of the igus® high-performance polymers convinced JDM Innovation GmbH.