Case study- increasing productivity with multi-component injection molding

The need to streamline and improve quality is what continuously drives us. The following is an interesting customer case study about just such a process that ended successfully with the adoption of advanced technology - multi-component injection molding
January 18, 2022

When planning the production process of a new product we can choose from among varied and technologically diverse production processes. These are characterized by, among other things, differences in cycle time, personnel costs, product quality and reject level. Some technologies will require additional manual intervention, some will be based on automation processes and others will fall somewhere in between.

The following is a customer case of one of our leading customers at Rion – Maytronics. An internationally successful company, demand for its products increased particularly during the Corona period. The company’s growth rate is impressive, rising from year to year, consequently boosting our growth as a leading sub-contractor as well.

The Product   –Brushes with Thin-Sided Fins

The product envisioned a brush consisting of two parts: the core of the product made of a rigid cylinder, enveloped all around with brushes made of flexible and thin-sided fins.

The Challenge  – Improve the Production Process

Originally, long before we received the product, the two parts were sewn together. The cylinder and fins were manufactured separately, with the fins manufactured in the form of a mat and sewn on to the hard cylinder core. This process entailed considerable work time, the efficiency was all but nil, and the quality of the final product and bonding of the two parts was poor.

Beginning to Manufacture at Rion, Over-Molding

To improve the prior manufacturing process the customer decided to transition to manufacturing using injection molding based on over-molding technology. However, this change posed challenges, primarily improved adhesion of the two parts to each other.

Two years ago, when we received the project, we were successful in working out the design, developing an efficient production process and manufacturing a quality product, all with the joint efforts of our Molds Department, injection technology personnel, and of course the customer’s injection team. The professional abilities of our Molds Department to provide in-house support with respect to complex molds helped us make the necessary changes and adaptations in order to improve production. We also spearheaded a process of changing the raw material in order to increase the compatibility between the two parts. 

תמונה 1: מברשת בטכנולוגיה דו-קומפוננטית בריאון. המברשת מורכבת מגליל פנימי קשיח וסנפירים גמישים, דקי דופן העוטפים אותו. תמונה 1: מברשת בטכנולוגיה דו-קומפוננטית בריאון. המברשת מורכבת מגליל פנימי קשיח וסנפירים גמישים, דקי דופן העוטפים אותו.

Transitioning to Automation for Process Streamlining

The initial process entailed manually placing the rigid cores into the mold in order to perform the additional injection of the fins onto them. Here also we have seen very quickly the streamlining potential and took the initiative of adding automation to enable a continuous process. A robot placed the hard pipe in the mold and also extracted the finished product and placed it on the conveyor belt, reducing personnel in the production process by one entire employee! The entire automation, planning, execution, and integration process was carried out by our Automation Department, with the support of the Molds Department to make the necessary changes to the mold.

Development Continues – Transitioning to Multi-Component Injection molding

Why make do with the good if you can do even better? Indeed, despite the significant improvement achieved in product production and quality, our customer wanted to improve the strength of the bonding between the two parts. This can be accomplished when the material is still hot and close to its molten state during the injection process.

The breakthrough occurred about a year ago when we advanced towards the production of a similar product using multi-component injection molding. Specifically, when we understood that if this succeeded we would be able to transition other products to the multi-component injection molding world. Multi-component injection molding saves the use of one injection machine, performs the entire process with a single mold, provides additional personnel savings and facilitates the logistics.

In planning these products, one of the biggest challenges was the location of the material gate entry points that were especially close to one another. One was performed at a special angle and the other through an incision in one of the fins. A special hot runner system was tailored, mainly to achieve extensive compactness as well as durability of the special injected materials.

This was the first multi-component injection we carried out at Rion. Despite the lack of specific experience in this field, our extensive knowledge in mold-planning worked in our favor and the project was deemed a success! Cycle time improved significantly, the number of rejects decreased, and the logistical process was shortened, saving on the maintenance of two separate molds. Another significant advantage was the considerably improved product lifetime that was achieved owing to a good adhesion between the two parts that are molded together even before the polymer reaches its final form.

The project upgraded the capabilities of our Molds and Engineering Departments as well as the professional knowledge of our technologists who contended with a new challenge. All the molds were designed at Rion Israel, and their manufacturing process was carried out abroad by our authorized suppliers and under the strict oversight of our team abroad.

A New Machine for a New Technology

To produce the product, we have acquired a special multi-component injection molding machine from ARBURG, with 400 ton clamping force, a rotating table and indexing capability. We engaged with ARBURG at the initial planning stage of the mold in order to best adapt the machine for the needed application. Several meetings were conducted between our technology personnel and the ARBURG team at its development site to ensure that the design and the selected machine were the optimal choice.

Continued Development

Another development in manufacturing this product is the current transition to multi-component injection molding with a double-cavity mold, carried out nowadays. The aim is another leap in process streamlining and cycle time. An additional multi-component injection molding machine, with 450 ton clamping force, was purchased and has just been installed on our new production floor. It will serve us for additional, longer, products from the same series.

The customer case presented here is interesting in its complexity but is not unusual in our activity field. We are always on the lookout for new ways to technologically streamline processes for our customers. Our industry faces the challenge of recruiting quality personnel, which is why we do the utmost to transition to automatic processes that will reduce this dependence while shortening cycle times and improving quality.

תמונה 2: מכונה דו-קומפוננטית שניה בריאון, בתהליכי התקנה באולם הייצור החדש. תמונה 2: מכונה דו-קומפוננטית שניה בריאון, בתהליכי התקנה באולם הייצור החדש.