Cut maintenance: Position hot melt jetting heads correctly

author Maurizio De Cubellis, Area Sales Manager Schweiz
The positioning of hot-melt adhesive jetting heads in a production plant has a direct impact on subsequent maintenance requirements. Therefore, discuss the key details for maintenance-friendly installation with your equipment manufacturer during the planning phase. This will ensure that maintenance-related production downtimes are not unnecessarily prolonged.


Easy-to-maintain positioning of Volta application heads in a packaging system

When deciding on the positioning of an adhesive application system, equipment manufacturers and the customer's maintenance personnel usually have different priorities. While designers generally strive for the most compact and space-saving installation possible, service teams focus on aspects such as accessibility and ease of maintenance. 

 

Adhesive application bottom-up, top down or horizontally? 

In practice, space-saving positioning can result in the application heads applying the adhesive to the substrate from the bottom up. However, this significantly increases maintenance requirements, as adhesive can drip onto the application nozzle. The high temperatures at the nozzle cause the adhesive to burn and form a hard crust around the nozzle. To ensure the quality of the application and not reduce the lifetime of the nozzle, significantly shorter cleaning intervals are therefore necessary compared to top-down or horizontal application.

Two application heads encrusted with burnt hot melt adhesive, which apply adhesive to the substrate from bottom up.Adhesive application from bottom up implies more maintenance efforts. 

In the worst case, the dripping adhesive can even get into the solenoid valve. Then replacing the valve—including production downtime—is unavoidable.

Tip No. 1: When planning the production plant, make sure to position the jetting heads such that the adhesive can be applied top down to the substrate or from the side. 

 

When bottom-up adhesive application is unavoidable

Bottom-up covers for Robatech jetting heads prevent dripping adhesive from contaminating the application nozzle. Bottom-up covers for pneumatic (left) and electrical jetting head (right). 

If applying bottom-up adhesive application cannot be avoided, make sure to specify during system planning that the jetting head is equipped with a bottom-up cover. This catches any adhesive that drips back and directs it past the side of the jetting head. To do this, the jetting head must be mounted at an angle of about 10° in product feeding direction. 

Drawing of the SpeedStar Compact application head installed at a 10° angle in the product feeding direction for bottom-up hot melt application.

Tip No. 2: When applying adhesive bottom up, it is helpful to plan for bottom-up cover and/or tilt the application head 10° to the production feed direction in order to avoid soiling of the application nozzle and damage to the solenoid valve as far as possible.

 

Keep the system clean with a collection tray 

What you may not have known: When hot melt adhesive is applied, a barely visible, extremely thin thread forms at the application nozzle. Over time, this forms a drop or what is known as “angel hair.” If you want to avoid contaminating products or moving parts of the production system, you should ensure that a collection tray is installed when planning the system.

Collection tray, mounted below a Volta application head from Robatech, used in a packaging system.It’s worth installing a collection tray.

Tip No. 3: Mount jetting heads in such a way that drops or threads detaching from the nozzle fall directly into the collection tray or into a designated empty space. 

 

The holder: a small detail with a time-saving effect 

Many machine builders attach the application head to a round steel bracket as standard. For maintenance personnel, this means that after cleaning or replacement, the exact position and angle of the jetting head must be determined again through time-consuming test applications. Confined space in the plant can make alignment work difficult.

The flat steel holder offers a more maintenance-friendly alternative. Here, the angle and position of the application head are clearly visible after removal for maintenance. Reassembly can be carried out much more quickly and easily.

Tip no. 4: A flat steel holder can simplify and speed up removal and reassembly for maintenance. 

 

Good accessibility or small footprint? 

Ongoing maintenance of a pneumatic application head in a production plant. Good accessibility allows maintenance personnel to complete their tasks quickly. 

The application nozzle, filter, solenoid valve, and jetting element are among the typical wear parts of a pneumatic application head. Accordingly, periodic installation and removal of the jetting head is part of routine servicing. However, if space is too confined, servicing can become complicated and take significantly more time.

Tip No. 5: Check with the machine manufacturer to ensure that there is sufficient space for maintenance work on the application head. It is also worth noting that electric jetting heads require less maintenance and are more compact – an advantage that benefits both design and service. 

 

The trick with the angled plug-in connector  

What if space is very limited? In such cases, you can use an angled plug-in connector. This allows the solenoid valve to be installed at a 90-degree angle, creating additional space in confined machine rooms.

Application head positioned horizontally thanks to angled plug-in connector Angled plug-in connectors can be used to position application heads in a space-saving manner. 

Tip No. 6: In many cases, an angled plug-in connector significantly improves accessibility to the solenoid valve and the jetting head. It also opens up further options for designers to combine compactness and ease of maintenance.

Tip No. 7: Once again, our recommendation applies: an electric jetting head is inherently more compact and requires less maintenance than a pneumatic one.

 

Would you like more cost-saving tips for plant design? 

Request our free guide on planning systems with hot melt jetting heads! You will learn howto avoid typical mistakes when configuring and setting up a hot melt application system and how to optimize your dot and bead application. Of course, we have also compiled all our tips on reducing maintenance requirements for you in this guide.

REQUEST THE GUIDE

 
author

Maurizio De Cubellis, Area Sales Manager Schweiz

Maurizio De Cubellis has been advising companies in Switzerland on industrial adhesive application for 16 years. He now shares his most valuable tips in a practical guide.

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