Targeted Lubrication in Plastics Injection-Molding Machines


As in most manufacturing processes, higher machine availability, with less unscheduled downtime, is a key factor in productivity and profitability. Reduced maintenance costs and greater reliability during production planning also result from predictive maintenance practices. Smart data analyses enable situation- or performance-related actions by the machine control system. The lubrication of electric and hybrid ALLROUNDER molding machines from Arburg provides an excellent example.

The electric toggle-type clamping units on the machines are optimized for predictive maintenance. Here, in addition to the toggles and planetary roller screw drives, all the guides for the moving mold-mounting platen, the drive platen and the ejector are integrated into the central automatic oil lubrication system.

An electric pump supplies several lubrication channels, which are controlled via switching valves, pressure switches and dosing elements. Dosage of the oil itself is performed locally via individual dosage elements in close proximity to the lubrication points.

Monitoring of lubrication lines

This more technically complex design has the advantage that the pressure in the lubrication lines right through to the dosage element at the lubrication point can be monitored. Broken or kinked lines are reliably detected by the pressure switch and the machine is stopped before inadequate lubrication takes place. The used oil is either recirculated or separated, simplifying disposal.

With the integration of so many lubrication circuits into the automatic central oil system, numerous manual lubrication points have been eliminated from the toggle-type clamping units. To further simplify preventive maintenance, grease lubrication points are connected by steel lines to one central and easy-to-access lubrication point outside the machine guarding panels.

Lubrication during production

As a result, there is no need to remove guards or dismantle any parts of the machine. These measures significantly reduce the time and cost of maintenance, while also providing greater process reliability. Because lubrication can take place while the machine is running and without interrupting production, machine availability also increases.

Integration of central oil and grease lubrication is already standard on mid-sized electric and hybrid ALLROUNDERs and on the general purpose GOLDEN ELECTRIC machine series. However, ARBURG engineers are going a step further by devoping performance-related lubrication.

Process-dependent lubrication

Instead of defining lubrication intervals based only on the number of cycles, lubrication requirements will be individually calculated for each application depending on such parameters as clamping forces, speeds, strokes and times. Extensive tests are currently underway during which new machines are compared with “run-in” machines. Initial results reveal the potential of smart data analyses in this area and, depending on the machine size and application, lubricant consumption can be reduced by up to 30 percent.

The improvements for predictive maintenance of the ALLROUNDER toggle-type clamping units clearly demonstrate how digitalization can progressively reduce the cost of operating injection-molding machines while, simultaneously meeting productivity goals and project deadlines.

In the final analysis, these are decisive factors when it comes to increasing the competitiveness of injection-molding companies and reducing costs.


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