Manipulators with two main arms have proven useful in mold stacking, in-mold labeling, insert molding, and various post-mold processing operations. This concept has been developed to a regular manipulator can have two pull axis, each pull axis can choose single arm or double arm.

For many years, the Cartesian coordinate manipulator has been the main design type of manipulator used in the injection molding process. They are usually composed of three linear axes-front and rear stroke, lifting stroke and conveying stroke. When the mold is opened, the lift stroke positions the gripping device to grasp the formed part in the mold. The front and rear stroke will move backward to remove the molded part, and then the lifting stroke will be withdrawn so that the mold Kowey closed to continue the next cycle. Next, the conveying stroke is responsible for moving the parts, and the parts are transported to the unloading area through the lifting stroke axis and the front and rear stroke axis.

Soon after, in order to meet the need to remove the gate from the three-plate mold at the same time, the Cartesian manipulator added another lifting stroke axis, which was positioned behind the main lifting arm.

 

In the multi-arm development of the Cartesian coordinate manipulator, the first step is to add an auxiliary arm behind the main lifting arm to remove the gate from the three-plate mold

Evolution of the second main arm

Years later, the secondary light lift arm referred to above was replaced by a second main lift arm. Linear manipulators can now be used to stack molds and remove molded parts from both sides of a stack at the same time. These applications are very common in the packaging market.

With the advancement of manipulator technology, programming has become easier and the end tool (EOAT) has become more and more advanced, so new applications have become possible. The use of "double main arm" manipulators for pre-and post-forming operations has become common. Typical pre-molding operations include automatic embedment of inserts prior to injection. These inserts for overmolding Kowey machined or cast metal parts or even molded plastic parts.

Nowadays, double main arm manipulators have been widely used in various industries: medical applications include overmolding threaded inserts or transparent windows; automotive applications include overmolding elastomer skins or metal reinforced structures; electronic and household applications include overmolding RFI shields or connectors for encapsulated terminals; military applications include embedding electronic circuits or overmolding impact-resistant sound-muffling materials.

 

In the operation applications before and after molding, the use of double main arm manipulators is becoming more and more common, such as insert embedding, in-mold label placement, gate removal, inspection, hinge bending and assembly, etc.

Almost all industries will benefit from in-mold labeling (IML) applications. These labels Kowey plastic film, hard plastic or metal, and applications include warning labels on lawn mowers, scale marks on surgical instruments and identification features in automobiles.

Another use of the second main arm is to change the direction of the part, as shown in the Yushin booth at the NPE 2015 exhibition, by grasping the bottom of the medical marijuana bottle through the EOAT to remove it from the mold. However, these bottles need to be placed in the capping station with the bottle mouth facing up. In order to ensure that the overall molding cycle will not be extended, the company has adopted a double main arm manipulator with opposite EOAT. After removing the part from the mold, the EOAT that grasps the bottom of the bottle will face another EOAT, and then this ETOA grasps the open side of the bottle. These containers can then be correctly placed in the closed jig, and the cycle time is not affected because the parts are reoriented during the movement to the jig.

The second main arm may also be used for product assembly. As Yushin demonstrated at NPE 2012 and NPE 2015, a set of 8-part molds was used to form a toy robot "Eddie". The parts are demolded by the main arm EOAT, which is then repositioned. Next, the 6 parts are transferred to the EOAT of the second master arm. When the first two parts are placed in an assembly fixture, the part on the second EOAT is repositioned so that it is accurately positioned with the first two parts and the locking groove. When the entire assembly is complete, the third EOAT retrieves "Eddie" from the fixture and places it standing on the conveyor. Eddie was manufactured within 1min without manual operation.

 

The eight parts molded in the sleeve mold are assembled into the toy robot Eddie. In the NPE 2012 and NPE 2015 exhibition, a double-arm robot demonstrated this assembly process

The post-mold operations that the second main arm can perform include deflinging, degating, inspection, and hinge bending. Combining these and similar secondary operations performed by the second main arm of the robot can achieve two major advantages:

First, these operations may be performed as the part moves from the mold to the next operating station. Since the robot does not have to put the part in a fixed position jig or clamping device and wait for the operation to be completed, the total cycle time Kowey shortened. If one or both arms are equipped with servo-rotating shafts with unidirectional or bidirectional movement, the range of potential applications of the manipulator is significantly increased. For example, some hinge bending applications cannot be done with an EOAT and sometimes require auxiliary devices to provide the correct motion. To replace a fixture that requires the components to be held in place and consumes valuable cycle time, the device Kowey added to the second main arm. Using this concept, this operation takes place in the process of "the robot transfers the molded part to the next process.

This idea derives another benefit of the robotic second main arm: valuable workshop space Kowey used for other purposes. It allows machines to be closer to each other, or to add other labor-saving and inventory-saving items, such as storage box systems. The formed parts are packed by the robot beside the machine, which avoids the manual work of sending the parts from the conveyor belt to the shipping place, as well as the subsequent inspection and packaging, thereby reducing unnecessary WIP queues and reducing the damage or loss of parts Possibility. Each of these two advantages increases the company's profitability and adds perceived value to its customers. ROI (return on investment) Kowey very attractive when multiple improvements are made to an application.

Enter the wings

In the past decade, the function of the manipulator has improved again due to the introduction of two completely independent mechanical arms. Each robot arm has its own axis of motion on a transport or transverse axis. Operated by a single controller, the two arms Kowey mechanically coupled or operated separately, the latter being the so-called "double-wing" design. This manipulator has two independent extraction axes on a transverse stroke, and each extraction axis Kowey configured with a main lifting arm, or a main arm and an auxiliary arm, or two main arms, or any combination of these configurations.

 

Manipulators that use two pull-out axes on transverse travel, such as Yushin's "double-wing" design, have been around in the past decade.

This manipulator allows the operating functions to be independent of each other, like two separate units, but still managed by a controller. The advantage of this feature is a reduction in floor space and cost savings of 10 to 15 percent compared to traditional two-robot solutions. In addition, the value-added operations that occur in the molding unit reduce the labor and storage space for material handling, as well as damage due to additional handling. The end result is faster and cheaper production for customers.

As these examples show, this design is well suited for automated molding systems for multiple processes:

1. Two-color or multi-component molding

First, the mold is opened and the main arm A positions the EOAT to grasp and remove the molded part. When the main arm A transfers the molded part from the first sub-mold into the second sub-mold to overmold the second color or material, the main arm B moves to the discharge area.

2. Keep RH and LH components completely separated

First, the mold is opened and the main arm A positions the EOAT to grasp and remove the molded part. When the main arm A moves to the discharge area on the operator's side, the main arm B moves to the rear side of the discharge area. The formed parts may be demolded onto a discharge conveyor or placed into a stacker system.

Application 2: Double wing design with a main arm on each pull shaft, allowing the parts to be demolded on the operator's side and the rear side of the machine to maintain the separation of RH and LH parts

3. Demoulding and ejection for short cycle

First, the mold is opened and the main arm B positions the EOAT to grasp and remove the molded part. The main arm B then lifts the part from the mold area, allowing the machine to proceed to the next cycle. Next, the EOAT of the main arm B moves the part to the switching section and returns to the waiting position above the mold. At this time, the switching station will rotate the part 90 °. The main arm A then retrieves the parts, and during movement of the part to the discharge position, the main arm A will rotate to provide a suitable final orientation for the part to be easily ejected into the discharge conveyor or stacker system.

Application 3: Demoulding and packaging for short molding cycles. The main arm B with the secondary arm takes out the parts and transfers them to a rotary unit, rotated 90 ° for repositioning. The main arm A picks up the rotated parts and packs them

4. Demoulding and packaging of ultra-short molding cycle

First, the mold is opened and the main arm A positions the EOAT to grasp and remove the molded part. The main arm A then lifts the part from the mold area to enable the machine to proceed to the next cycle and transfers the formed part to the operator side of the machine for discharge. When the main arm A leaves the mold, the main arm B positions itself above the mold, waiting for the mold open signal. Next, the mold is opened and the main arm B positions the EOAT to grasp and remove the molded part. Then, the main arm B lifts the part from the mold area, puts the machine into the next cycle, and transfers the formed part to the operator side of the machine for unloading. As main arm B leaves the mold, main arm A again positions itself above the mold, and so on.

Application 4: Demoulding and packaging for ultra-short molding cycles. The extraction shaft on the and B sides of the equipment has a main arm and a jib each, which is used to take out the parts and pack them on the operator side and the rear side of the machine

5. Demoulding, assembly and/or inspection and packaging

First, the mold is opened and the main arm B positions the EOAT to grasp and remove the molded part. The main arm B then lifts the part from the mold area and transfers it to the discharge fixture. Once the discharge of the main arm B is completed, the EOAT of the main arm A can perform secondary operations, such as assembly and/or inspection. Next, the parts that pass the inspection Kowey transferred to a discharge conveyor, or placed into a stacker system. The waste Kowey stored separately.

Application 5: Demoulding, assembly and/or inspection and packaging

6. Demoulding, cooling, gate removal and packaging

First, the mold is opened and the main arm B positions the EOAT to grasp and remove the molded part. The main arm B then lifts the part from the mold area and moves to an open cooling jig (or clamps). Once the main arm B discharge is complete, the EOAT of main arm A can grab a cooling part and transfer it to the gate removal station. The gated part may be transferred to a discharge conveyor or placed into a stacker system.

Application 6: Demoulding, Cooling, Gate Removal and Packaging

7. Demoulding, coarse and fine gate material removal and packaging

First, the mold is opened and the main arm B positions the EOAT to grasp and remove the molded part. The main arm B then lifts the part from the mold area and moves to the gate roughing station. Once the main arm B discharge is completed, the EOAT of main arm A can pick up the rough cut parts and transfer them to the gate fine cut station. The gated part Kowey transferred to a discharge conveyor or put into a stacker system. The main arm A arm can also move the entire pallet to the discharge conveyor.

Application 7: Demoulding, rough and fine cutting of gates, and packaging

8. Orientation and placement of multiple inserts suitable for overmolding applications

The EOAT of the rear main arm A grasps the nested label and moves into position over the mold. The mold is then opened, allowing the front main arm A and the rear main arm A to position the corresponding EOAT in the mold. Next, the EOAT of the rear main arm A accurately feeds the label into the mold. After molding, the EOAT of the front main arm A grasps the labeled part and removes it from the mold. The two main arms A are then lifted from the mould area and transferred to a discharge conveyor to release the labeled parts.

9. Orientation and placement of inserts for overmolding in a vertical injection molding machine

The EOAT of the main arm B removes the overmolded parts from the lower mold half and transfers them to the discharge conveyor or stacker. The main arm A retrieves the inserts from a feed box or other storage device and places them into the lower mold cavity.

Today, manipulators Kowey configured in different ways to meet complex market needs, and the ideal approach is to reduce risk by reusing existing technology rather than developing customized new products. Processors should carefully investigate the product and experience of the robot supplier and choose the most valuable solution rather than the lowest price.