Hotmelt (Hotmelt Overmolding) Process
Hotmelt (Hotmelt Overmolding) Process with Dr. BOY Injection Molding Machines
The hotmelt process is a specialized manufacturing technology in which thermoplastic hotmelt materials with low melting temperatures are applied to a component or used to join different components by means of injection molding. By enabling bonding, sealing, fixing, and protective functions within a single production cycle, hotmelt injection offers a faster, cleaner, and more repeatable solution compared to conventional adhesive bonding, assembly, and coating methods. Injection molding machines from Dr. BOY provide the precise temperature control, stable low-pressure injection, and high repeatability required for hotmelt processing through a compact and reliable machine architecture.
What Is the Hotmelt Process?
The hotmelt process is based on melting EVA-, PO-, PA-, TPU-based, or specially formulated hotmelt materials, injecting them into a mold, and allowing them to solidify rapidly through cooling. These materials are typically used for:
Bonding
Sealing
Electrical insulation
Mechanical fixation
Protective coating
Since hotmelt injection is a solvent-free process and does not require curing, cycle times are very short and the process offers significant environmental advantages.
Suitability of Dr. BOY Machines for the Hotmelt Process
Compared to conventional thermoplastics, hotmelt materials have lower viscosity and a much narrower temperature processing window. For this reason, injection speed, pressure, and temperature must be controlled with high precision.
Dr. BOY injection molding machines provide:
Stable filling at low injection pressures
Precise barrel and nozzle temperature control
Smooth injection transitions
Vibration-free and highly repeatable mechanical movements
These characteristics make Dr. BOY machines an ideal platform for hotmelt applications.
The compact machine design and tie-bar-less clamping system ensure easy access to hotmelt molds and specialized dosing units.
Plasticizing and Temperature Control
Temperature is the most critical parameter in the hotmelt process. If the material is not sufficiently fluid, mold filling becomes difficult; excessive temperature, on the other hand, can lead to material degradation and performance loss.
Dr. BOY machines maintain hotmelt materials at optimal viscosity through highly precise barrel and nozzle temperature control. Stable thermal management contributes to:
Homogeneous filling
Consistent bonding performance
Uniform coating on part surfaces
Injection and Overmolding
Hotmelt processing is most often applied onto inserts or semi-finished components. Electronic circuit boards, filter elements, textile surfaces, or plastic housings can be encapsulated or fixed using hotmelt materials.
Thanks to the precise injection control of Dr. BOY machines:
Thin layers can be applied in a controlled manner
Overflow and flash risks are minimized
Sensitive components are encapsulated without damage
This is a major advantage in electronic and medical applications.
Cooling and Cycle Time
Hotmelt materials solidify purely through cooling and do not require curing, resulting in very short cycle times. The stable mold clamping and balanced mechanical movements of Dr. BOY machines allow cooling times to be optimized.
As a result:
High production speeds
Low cost per part
A process structure suitable for serial production
can be achieved.
Automation and Cell-Based Production
Hotmelt injection delivers maximum efficiency when combined with automation. Dr. BOY machines can be easily integrated with robotic part handling, automatic hotmelt dosing units, and conveyor systems.
This approach:
Minimizes human contact
Improves process repeatability
Supports cleanroom and high-precision manufacturing
Typical Hotmelt Applications
Hotmelt processing with Dr. BOY injection molding machines is widely used in:
Encapsulation of electronic boards and sensors
Sealed joining of filter and membrane elements
Cable and connector sealing applications
Fixation of textile and nonwoven products
Bonding and coating of disposable medical products
Why Choose Dr. BOY for the Hotmelt Process?
Dr. BOY delivers the precise temperature control, stable low-pressure injection, and high repeatability required for hotmelt injection through compact and energy-efficient injection molding machines. Easy mold access, automation-ready design, and low scrap rates make Dr. BOY machines a strong solution for hotmelt applications.
For production environments where bonding, sealing, and functional integration are critical, Dr. BOY provides a reliable, clean, and sustainable manufacturing platform for hotmelt processing.