ADVANCE INJECTION MOULD DESIGN 01 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPLIT MOULD 02 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPLIT MOULD It is required for components incorporates a recess or projection right angle to the line of draw, to relieve the undercut before the moulding is removed. A moulding which has a recess or projection is termed as undercut moulding. The undercut may be external, internal, local part of the component. Two or more parts of the cavity closed together in a chase bolster by using locking heels during injection. 03 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 1.1 Fig: 1.2 04 CORPORATE TRAINING AND PLANNING

VISIBLE LINE ON MOULDING Parting line: The line formed on the molding surface where the core and cavity closed together. Joint Line: The line formed on the molding surface where the splits (side cores) are closed together. 05 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SLIDING SPLITS The splits are positioned in guides on a flat mould plate are actuated by mechanical or hydraulic system and those are held together by locking heels which project on the other mould half. The splits are possible to mount on either the moving or fixed mould plate. 06 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 1.3 Fig: 1.4 07 CORPORATE TRAINING AND PLANNING

GUIDING AND RETENTION OF SPLITS - SLIDING FIT Fig: 1.5 Fig: 1.6 08 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 1.8 Fig: 1.7 09 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING DESIGN CONSIDERATION OF SPLIT MOULD The side movement should ensure the split halves always come together in the same plane. In split mould all the parts should have enough strength to withstand the force applied to the splits by the operating system. It should allow smooth movements of splits. 10 CORPORATE TRAINING AND PLANNING

SPLIT DESIGN CONSTRAINTS Amount of splits movement and delay period required. Ease with which the molding can be removed. Whether a short or long production run is required. Whether the available machines are programmed for ancillary cylinder control. Whether molding inserts are to be incorporated. 11 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPLIT MOULD ACTUATION METHODS Finger cam actuation method Dog-leg cam actuation method Cam track actuation method Hydraulic actuation method 5. Angled-lift splits 6. Spring actuation system 12 CORPORATE TRAINING AND PLANNING

1.FINGER CAM ACTUATION 13 Fig: 1.9 Fig: 1.10 Split in open condition Sleeve ejector pin Split in open condition Split in closed condition Fig: 1.9 Fig: 1.10 13 CORPORATE TRAINING AND PLANNING

FINGER CAM ACTUATION MOULD FOR CAP COMPONENT CORPORATE TRAINING AND PLANNING

FINGER CAM MOULD FOR LEDHOLDER CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING FINGER CAM PIN Hardened, circular steel pins, termed finger cams are mounted at an angle in the fixed mould plate. Length and angle of the finger cam determine the distance traversed by each split across the face of the mould plate. 14 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING FINGER CAM PIN M = splits movement  = Angle of finger cam, 10-25 L = working length of finger cam C = clearance (0.75mm) Fig: 1.11 15 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CALCULATION The finger cam movement can be computed by the Formula M = (L sin ) – (C / cos ) If the required movement is known, the following formula used to determine the finger cam length. L = (M / sin ) + (2C / sin 2) Where, M = splits movements,  = Angle of finger cam, 10-25 L = working length of finger cam C = clearance (0.75mm) Cam diameter is usually 13 mm. 16 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING 2. DOG - LEG CAM ACTUATION This actuation system is used where a more splits delay time is required compare to finger cam actuation method. 17 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING DOG-LEG CAM Fig: 1.12 18 CORPORATE TRAINING AND PLANNING

DOG-LEG CAM ACTUATED MOULD Split in closed condition Split in open condition Fig: 1.14 Fig: 1.13 19 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING DOG LEG CAM ACTUATED SPLIT MOULD M = movement of each split, La= angled length of cam, Ls = straight length of cam,  = Cam angle, C = clearance, D = delay, e = length of straight portion of the hole. 20 CORPORATE TRAINING AND PLANNING Fig: 1.15

CORPORATE TRAINING AND PLANNING CALCULATION Formula for calculating the opening movement, the length of cam, and the delay period M = La tan  - C La = (M + C)/ tan  D = (Ls – e) + (C/tan ) Where M = movement of each split, La= angled length of cam, Ls = straight length of cam,  = Cam angle, C = clearance, D = delay, e = length of straight portion of the hole. 21 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING 3. CAM TRACK ACTUATION This type of actuation system is used for components having under cut which requires more delay period Due to external fitment of cam track the mold actuation system becomes simpler and mold cost is reduced. The cam track is machined into a steel plate attached to the fixed mould half. A boss fitted to both sides of the split runs in this cam track. The movement of the splits accurately controlled by specific cam track design . 22 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CAM TRACK PLATE Fig: 1.17 Fig: 1.16 23 CORPORATE TRAINING AND PLANNING

SLIDING SPLIT MOLD (CAM TRACK PLATE ACTUATED) Fig: 1.18 24 CORPORATE TRAINING AND PLANNING

ACTUATION MOLD IN CLOSED POSITION ASSEMBLY OF CAM TRACK ACTUATION MOLD IN CLOSED POSITION Fig: 1.19 25 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CAM TRACK M = movement of each split, La= angled length of cam track, = cam track angle, C = clearance, D = delay, R = radius of boss Fig: 1.20 26 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CALCULATION M = La tan  - C La = (M + C) / tan  D = Ls + C/ tan  + r ( 1/tan  - 1/sin  ) M = movement of each split, La= angled length of cam track,  = cam track angle, C = clearance, D = delay, R = radius of boss 27 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING 4. HYDRAULIC ACTUATION The splits are actuated by hydraulic system. It is independently opening movement of the mould. The splits can be operated automatically at any specific time by the operating program of the machine ADVANTAGES Cycle time less Large delay movements and large split movements can be achieved 28 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING DISADVANTAGES The mould is more bulky as compared with the other designs Mould setting more difficult and the hydraulic system has to be connected each time the mould is set up. 29 CORPORATE TRAINING AND PLANNING

HYDRAULIC ACTUATION OF SPLITS Fig: 1.21 30 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING ANGLED-LIFT SPLITS In this method the splits are mounted in a chase-bolster, which forms part of the moving half of the mould. The splits are moving outward with an angular motion which relieve the undercut portion of the molding and retraction of the split alignment is controlled by using spring actuation or cam track actuation 31 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING ANGLED LIFT SPLITS DIAGRAM Fig: 1.22 Fig: 1.23 32 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING TYPES OF ANGLED LIFT SYSTEMS Angled guide dowel actuating system Cam track actuating system Spring actuation. 33 CORPORATE TRAINING AND PLANNING

DOWEL ACTUATING SYSTEM ANGLED GUIDE DOWEL ACTUATING SYSTEM The Guide dowels are fitted at an angle to the underside of each split which passes through holes machined at an angle in the chase-bolster. When the ejector system is actuated, the relative movement between the ejector plate and the chase-bolster causes the guide dowels to move forward at an angle corresponding to the splits which opens. 34 CORPORATE TRAINING AND PLANNING

ANGLED GUIDE DOWEL ACTUATION Split in closed condition Fig: 1.24 35 CORPORATE TRAINING AND PLANNING

36  = Guide dowel angle. Fig: 1.25 Split in open condition CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING The convenient angle for the guide dowel is 10 it may be increased if large opening movement is required. The actual opening movement of each split calculated by the following formula. M = E tan  E = effective ejector plate movement,  = Guide dowel angle. 37 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CAM TRACK ACTUATING SYSTEM In this method the opening movement of the splits are controlled by a cam track. When the splits are actuated, studs fitted to each end of the split slide along this cam track. Actuation of the splits is by means of pin ejector system. The splits are fitted into an open channel type chase-bolster, which have wear plates. Studs, screwed into the splits, protrude into the cam track machined in the cam track plate which is attached to the bolster. 38 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CAM TRACK ACTUATION Fig: 1.26 39 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CALCULATION The opening movement of each split calculating by M = E tan  E = effective ejector plate movement,  = Cam track angle, usually 15 40 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPRING ACTUATION The opening movement of the split depends on the slot provided in the chase bolster and the spring effective expansion length. This ejection method is suitable for shallow undercut components. The ejector pin actuates the split, the spring exerts the a force to vertical direction, which maintains contact between the split and the angled wall of the chase-bolster and gives angled movement to the splits. Thus the splits get open. 41 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPRING ACTUATION METHOD Fig: 1.27 42 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPRING ACTUATION SYSTEM This actuation system is suitable for small straight and angled undercut components. In this method the compression springs are used to force the splits apart and utilizes the angled faces of the chase bolster to close them. The opening of split movement should be limited so that they will allow to re-enter the chase bolster when the mould is closed. The splits are mounted on the mould plate and retained by guide strips. Studs project from the base of the splits into a slot machined in the mould plate. The length of this slot therefore controls the opening movement of each split. A compression spring is fitted between the studs in a link-shaped pocket situated in the lower mould plate. The splits are held closed by the chase bolster. 43 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPRING ACTUATION Fig: 1.28 44 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SEQUENCE OF OPERATION The chase bolster holds the splits during the injection phase. The compression springs exerts a force to split halves immediately when the mould starts to open. The stud reaching the end of the slot in the mould plate stops the split movement. Continued movement of the moving mould half operated the ejector system to release the molding . 45 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CALCULATION The formula for calculating the splits opening movement is M = ½ H tan  Where M = movement of each split, Approximately H = height of locking heel = angle of locking heel Suitable angle for the locking heel is 20 to 25. 46 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SIDE CORES It is a local core mounted at an angle to the mould axis for forming a hole or recess inside the molding. This side core prevents the in-line removal of the molding hence, side core must be withdrawn prior to ejection . 47 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING TYPES OF SIDE CORE Internal Side Core Assembly The dog-leg cam actuation method The spring-loaded system External Side Core Assembly Side cores on the parting surface Side cores below the parting surface Angled withdrawal Curved side core 48 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING INTERNAL SIDE CORE ASSEMBLY In this method the side core is T-shaped is mounted in guides, which are securely attached to the moving mould plate. The retaining plate to the carriage secures the side core element.The actuation of the carriage is by means of a finger cam/dog leg cam method The carriage is locked in the forward position by the locking heel 49 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING DOG-LEG CAM METHOD OF ACTUATION Fig: 1.29 50 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING THE SPRING-LOADED SYSTEM The spring-loaded system is an operating method confined to those moldings that have very shallow undercuts or projections. 51 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 1.30 52 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING EXTERNAL SIDE CORE ASSEMBLY In this design, the side core is fixed to an extremely mounted carriage which is actuated by hydraulic or pneumatic means. 53 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 1.31 54 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CURVED SIDE CORE The core is withdrawing from the mould along the arc of a circle. It is suitable for components requires smooth curved internal hole Example: telephone hand set and pipe fittings. In this type of component the side core can be mounted on the parting surface of the mould. 55 CORPORATE TRAINING AND PLANNING

MOULDS FOR INTERNAL UNDERCUT COMPNENTS 05858

INTERNAL UNDERCUT An internal undercut is the internal protrusion or recess formed in the molding by using matching core or cavity. It is prevents a moulding from being extracted from the core in line of draw. 059

EXAMPLES OF INTERNAL UNDERCUT COMPONENTS Fig: 2.1 Fig: 2.2 060 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING FORM PIN A component, which has a local undercut portion, can be successfully moulded in the conventional mould by incorporating the undercut form on a pin. 061 CORPORATE TRAINING AND PLANNING

UNDERCUT COMPONENTS WHICH NEED FORM PINS ACTUATION Fig: 2.3 062 CORPORATE TRAINING AND PLANNING

TYPES OF FORM PIN EJECTION Form Pin : Straight action Form pin : angled action 063 CORPORATE TRAINING AND PLANNING

FORM PIN:STRAIGHT ACTION This design is normally used for components, which incorporate an undercut on one internal wall only. 064 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 2.4 Fig: 2.5 065 CORPORATE TRAINING AND PLANNING

FORM PIN: ANGLED ACTION The basic feature of this design is that the working face of the form pin is caused to move inwards relative to the core during ejection, thereby relieving the undercut. It can be used for components, which incorporate internal undercuts on one or more walls. 066 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 2.6 67 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CALCULATION The amount of withdrawal is calculated by the following relationship: M = E tan θ Where, M = the withdrawing movement E = ejection movement. θ = fitting angle of the form pin. 68 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPLIT CORE ACTUATION This split core may be moved forward either in a straight plane or an angled plane. 69 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SPLIT CORES-STRAIGHT ACTION This design is used for components, which incorporate an external undercut on one wall only. The moulding can be removed at right angles to the mould axis. 70 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 2.7 71 CORPORATE TRAINING AND PLANNING

SPLIT CORE ANGLED ACTION In this design the split core is caused to move inwards during the ejection stroke, thereby withdrawing the restriction and allowing the moulding to be extracted in the line of draw. The advantages of this method is that the withdrawing action automatic and the moulding does not have to be removed at right angles to the mould’s axis. This design can therefore be used for components with undercuts on opposing faces in addition to being used for components with an undercut on one wall only. 72 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 2.8 73 CORPORATE TRAINING AND PLANNING

STRIPPING INTERNAL UNDERCUT Suitability:  The shape of the undercut,  The elasticity of the material, and  Whether the external form permits expansion during ejection. 74 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 2.9 75 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING CURVED SIDE CORE Fig: 1.32 56 CORPORATE TRAINING AND PLANNING

MOULDS FOR THREAD COMPONENTS CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING MOULDS FOR THREADED COMPONENTS The threaded components are usually prepare for where the repeated disassembly or where the strength of assembly is required. The threads can be formed in by three methods: Cored or drilled holes with either thread cutting or thread forming using self-tapping type screws. Molded with local inserts. Molded thread formed by using unscrewing threaded inserts. CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING TYPES OF THREADS External thread. Internal thread. According to thread shape subdivided into continues and discontinuous thread. CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 3.1 Fig: 3.2 CORPORATE TRAINING AND PLANNING

COMPONENTS INCORPORATING THREADS Fig: 3.4 Fig: 3.3 CORPORATE TRAINING AND PLANNING

MOULDS FOR INTERNAL THREADED COMPONENTS The internal thread is an internal undercut in that the thread forms a restriction, which prevents the straight draw removal of the moulding from the core. The types of mould design for withdrawing the moulding, as follows:    Stripping (jumping-off) thread design    Fixed threaded core design    Loose threaded core design    Collapsible core design Unscrewing mould designs CORPORATE TRAINING AND PLANNING

STRIPPING (JUMPING) INTERNAL THREADS The moulding must be free to expand during ejection to permit the moulded undercut to ride over the restriction on the core. 2. The outside form of the component to be formed in a cavity, which is fully contained in one half of the mould. 3. The internally threaded component may be stripped (Jumped) from the core using the stripper plate design providing a roll thread and the plastic material has sufficient elasticity during the ejection phase. 4. This method is recommended for polyethylene (PE), polypropylene (PP) material. CORPORATE TRAINING AND PLANNING

STRIPPING INTERNALLY THREADED COMPONENTS Fig: 3.5 CORPORATE TRAINING AND PLANNING

FIXED THREADED CORE DESIGN In this method, the thread form is incorporated on a non-rotating core fixed to the moving mould plate. An integer type cavity forms the external shape of the moulding. In operation, when the mould is opened, the moulding remains on the core and is afterwards unscrewed by the operator by hand or using release devices. CORPORATE TRAINING AND PLANNING

FIXED THREADED CORE DESIGN Fig: 3.6 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING ADVAMTAGES Mould cost is cheaper than the unscrewing mould design because of its require ejector mechanism Maintenance cost is minimum as there are no moving parts within the mould. DISADVANTAGES This design particularly used for multi-impression moulds where the individual moldings to be unscrewed manually. Increases the moulding cycle time. CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING     LOOSE THREADED CORES This method is suitable for a large component incorporates a local internally threaded hole or has several internally threaded holes in close proximity to each other. Prevents automatic unscrewing thereby considerably reducing the cost of the mould. Where a number of holes are closely spaced, automatic unscrewing becomes impracticable. Because it require space for gear arrangement in automatic unscrewing operation. CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING LOOSE THREADED CORES Fig: 3.7 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING COLLAPSIBLE CORE This design is suitable for components having internal thread and internal undercut. The important advantage of this method over the rotating threaded core designs is that it eliminates the need for complex unscrewing mechanism. CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING COLLAPSIBLE CORE Fig: 3.8 CORPORATE TRAINING AND PLANNING

EJECTOR PLATE ASSEMBLY OPERATED USING COLLAPSIBLE CORE Fig: 3.9 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING UNSCREWING MOULDS High labour costs and other modern production requirements demand the maximum use of automatic operation. In an unscrewing type mould either the cores or the cavities are rotated to automatically unscrew the moldings from the mould. To provide the required rotary motion an unscrewing unit is fitted behind the moving mould plate in place of the conventional ejector unit CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Manually powered fixed rotating core design CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Manually powered fixed rotating core with gear transmission CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING POINTS CONSIDERED In the axially fixed core design, the threaded core is merely rotated to remove the moulding. In the extractor plate design, the extractor plate is actuated at the same time as the threaded core is rotated to remove the moulding. In the withdrawing rotating core design, the threaded core is rotated by sun & planet gear mechanism and withdraws the moulding from the core plate. CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING IMPRESSION LAYOUTS The pitch circle diameter . 2. The In-line layout. CORPORATE TRAINING AND PLANNING

MACHINE POWERED IN-LINE UNSCREW SYSTEM Fig: 3.12 CORPORATE TRAINING AND PLANNING

THE PITCH CIRCLE DIAMETER LAY-OUT Fig: 3.13 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING MULTIDAYLIGHT MOULD 01 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING MULTIDAYLIGHT MOULD It is a complex mould having more than one-daylight when the mould is opened. It consists of three main parts: Fixed mould plate or feed plate, Floating cavity plate or stripper plate, Moving mould plate. 0102 CORPORATE TRAINING AND PLANNING

TYPES OF MULTI DAY LIGHT MOULDS 1. Double day light, stripper plate mould 2.  Double day light, under feed mould 3. Triple day light, underfeed and stripper Plate mould. 0103 CORPORATE TRAINING AND PLANNING

DOUBLE DAYLIGHT, STRIPPER PLATE MOULD Suitability : The circular box-type moulding, which have thin wall section. Stripper plate: The stripper plate is a rectangular plate, has aperture to sliding on the core for ejection. It is mounted between the cavity plate and the core plate. These types of ejection will not leave any depression on the molding. 0104 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING The moulding and feed system are removed in the first day light between the stripper plate and the fixed mould plate from the cavity plate. Second daylight between the core plate and stripper plate for ejection. 0105 CORPORATE TRAINING AND PLANNING

STRIPPER PLATE EJECTION Fig: 4.1 Fig: 4.2 Fig: 4.3 0106 CORPORATE TRAINING AND PLANNING

DOUBLE DAYLIGHT STRIPPER PLATE MOULD Fig: 4.4 Fig: 4.5 Fig: 4.6 Fig: 4.7 Double Day Light With Underfeed Mould 0107 CORPORATE TRAINING AND PLANNING

DOUBLE DAY LIGHT WITH UNDER FEED MOULD An Underfeed mould is one in which the feed system is arranged to feed into the underside of the component. In this mould the extra plate is added behind the cavity plate to allow a runner system to be incorporated below the cavity or cavities. It consists of three main parts 1. Feed plate. 2. Floating cavity plate. 3. Moving mould plate. 0108 CORPORATE TRAINING AND PLANNING

USE OF UNDERFEED TYPE OF MOULD 1. Multi-point feeding can be accomplished on single-impression moulds and on multi-impression mould. 2. Off-centre feeding can be achieved for both single and multi-impression moulds. 0109 CORPORATE TRAINING AND PLANNING

TRIPLE DAY LIGHT WITH UNDERFEED AND STRIPPER PLATE MOULD A three-plate mold or triple daylight mould differs from a two plate in that it has two parting planes and the mold splits into three sections, every time the part is ejected. Since the mold has two parting planes, the runner system can be located on one, and the part on the other. Three plate molds are used because of their flexibility in gating location. A part can be gated virtually anywhere along its surface. 110 CORPORATE TRAINING AND PLANNING

TRIPLE-DATLIGHT, UNDERFEED-STRIPPER PLATE MOULD Fig: 4.8 Fig: 4.9 111 CORPORATE TRAINING AND PLANNING

A THREE PLATE MOULD ASSEMBLY Fig: 4.10 112 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING THREE PLATE MOULD   This mould is mostly prepared for multi impression circular cap components. It is the combination of stripper plate and under-feed system. 113 CORPORATE TRAINING AND PLANNING

STRIPPER PLATE MOVEMENT Fig: 4.11 Fig: 4.12 114 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SECONDARY SPRUE BUSH Multi daylight moulds are having two sprue bushes. Primary sprue bush is mounted at fixed plate backside. Secondary sprue bush is mounted in the floating cavity plate. 115 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING SECONDARY SPRUE BUSH Fig: 4.13 116 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING It is the simplest form of feed system. It is not practicable for all types of components. The shape of the component affects the design of the floating cavity plate, which in turn determines the type of feed system can be adopted and it requires the extra operation for removal of runner from the moulding. 117 CORPORATE TRAINING AND PLANNING

REVERSE TAPER SECONDARY SPRUE REVERSE TAPER SPRUE Fig: 4.14 118 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING REVERSE TAPER SECONDARY SPRUE Standard type of pin point gate is used. The main use of this sprue is to release the component with automatic de-gating in three-plate mould. Drawback of this method: the feed system is not free to fall when the mould is opened because the secondary sprues are retained within the floating cavity plate. The feed system is removed by hand if the basic underfeed mould design is used. 119 CORPORATE TRAINING AND PLANNING

UNDERCUT RUNNER SYSTEM SECTION VIEW Fig: 4.15 Fig: 4.16 120 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 4.17 121 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING DESIGN CONSIDERATION  The float period must be sufficient to permit the floating cavity plate to clear the reverse-tapered sprues before the puller pulls the sprue. Considerable runner deflection is necessary to ensure that the secondary sprues are not pulled back into their holes when the puller is actuated. To ensure that the puller is pushed back to its moulding position when the mould is closed, the diameter of the puller must exceed the width of the runner. 122 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING RUNNER STRIPPER PLATE The fixed secondary puller is fitted directly below each secondary sprue. To release the feed system from this fixed secondary puller a runner stripper plate is introduced between the feed plate and the floating cavity plate. 123 CORPORATE TRAINING AND PLANNING

UNDERFEED MOULD SECTION VIEW 01 Fig: 4.18 124 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING UNDERFEED MOULD Fig: 4.19 Fig: 4.20 Fig: 4.21 Fig: 4.22 125 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING STACK MOULD When two injection moulds are operated in tendem in the same molding machine it is called stack mould. Used for molding shallow, small parts in large quantities like tape cassettes. The cavities are located in two planes corresponding to two parting lines and are filled. The clamping force required is 15% higher than a standard mould. 126 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING It is a simplest mould design, from a runner point of view is a single-cavity, single-face mold arranged in back to back configuration of same impression or different impressions. The machine nozzle injects plastic directly into the mould cavity. The single-face mould can also be extended to a multi-cavity layout. The machine nozzle injects the melt into a runner system that feeds each individual cavity. It is suitable of which has the thin-wall injection molding with hot runner designs. 127 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING STACK MOULD IN IMM Fig: 4.23 128 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig: 4.24 129 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING TYPES OF STACK MOULD   FOUR-FACE (FOUR-LEVEL) STACK MOLDS 2.   THREE-FACE (THREE-LEVEL) STACK MOLDS 130 CORPORATE TRAINING AND PLANNING

1.FOUR-LEVEL STACK MOULDS Four-level stack molds quadruple output over single-face molds, and are suited to very high production volumes of shallow parts. Quick Change molds switch from one product to another in less than an hour in both single-face and two face stack mold applications. Two-cavity slack molds allow molding of large parts in a back-to-back configuration, thus doubling the machine capacity. 131 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING The four-face stack mold is two stack molds placed back to back and it increases the mold shut height.   It operates in the same molding machine as a conventional slack mold. Cycle limes identical to those of a conventional mold. Shot-to-shot changeover time of less than one hour required for both mechanically and air ejected parts in the stack mold. Machine shut height remains the same from one product to the next. 132 CORPORATE TRAINING AND PLANNING

2.THREE-LEVEL STACK MOULDS Three-level stack molds permit molding of deep-draw or tall pans to maximize the productivity of machine shut height. It is the development of a proprietary melt transfer system to pass the plastic across the mold parting line. The system avoids drooling on mold opening due to the self-decompression of the central hot-runner system. 133 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING The three-level stack mold uses triple valueless melt transfer system (VMTS) crossover nozzles to provide equal pressure and flow characteristics to the plastic melt to each cavity. This stack mold configuration fills in when a two-level mold cannot produce enough pans and a four-level mold is too large for the machine. Three-level stacks is used to mold both shallow draw (for example, packaging lids) and deep draw pans (such as tall containers). They can be combined with quick-change systems to give added flexibility to high-production tooling. 134 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING HOT RUNNER MOULD 01 CORPORATE TRAINING AND PLANNING

TYPES OF INJECTION MOULD COLD RUNNER 2. HOT RUNNER A runner is the channel in the mold that conveys the molten plastic material from the barrel of the injection-molding machine to the part. 02 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING COLD RUNNER MOULD The runner is cooled and ejected with the part. Every cycle, a part and a runner are produced. There are two major types of cold runner molds: Two plate and Three-plate mould. 03 CORPORATE TRAINING AND PLANNING

ADVANTAGES OF COLD RUNNER MOULD Mold requires less maintenance. The mold design is very simple and much cheaper than a hot runner system. Less skill to set up and operate. Color changes are also very easy, since all of the plastic in the mold is ejected with each cycle. 04 CORPORATE TRAINING AND PLANNING

DISADVANTAGES OF COLD RUNNER MOULD The waste plastic is generated. The runners are either disposed of or reground and reprocessed with the original material. This adds a step in the manufacturing process. Regrinding increases variation in the injection molding process, and decreases the plastic's mechanical properties. 05 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING HOT RUNNER MOULD The hot runner mould contains a heated runner manifold block, insulated from the rest of the mould keeps the runner permanently melt. The hot runner mould replaces the conventional sprue bushing with a hot sprue bushing or a heated nozzle. The polymer material directed to the mould cavities without heat loss and pressure loss. Large moulding like automotive dash board, bumpers, computer housing, multi colour moulding etc. are produced in this process. 06 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING HOT RUNNER MOULD In a three-plate cold runner mold the runner system must be reground and the material is reused. It is possible to eliminate the runner system entirely by keeping it fluid. The material is kept plasticized by the hot runner manifold, which is heated with heating element (like electric cartridges). The block is usually thermostatically controlled. Heater bands, which are individually controlled, can be mounted round the nozzle. The plastic is kept fluid and the injection pressure is transmitted through the hot runner manifold. 07 CORPORATE TRAINING AND PLANNING

Assembly of hot runner mould 08 Assembly of hot runner mould Fig: 5.1 CORPORATE TRAINING AND PLANNING

Hot runner mould section view 09 Hot runner mould section view Fig: 5.2 CORPORATE TRAINING AND PLANNING

TYPES OF HOT RUNNER MOULD A hot runner system is divided into two parts The manifold The drops . The manifold has channels that convey the plastic on a single plane, parallel to the parting line, to a point above the cavity. The drops, situated perpendicular to the manifold, convey the plastic from the manifold to the part. 10 CORPORATE TRAINING AND PLANNING

HOT RUNNER WITH EXTERNALLY HEATED MANIFOLD AND DROPS 11 Fig: 5.3 CORPORATE TRAINING AND PLANNING

TYPES OF HOT RUNNER SYSTEM Internally drops and manifolds. Externally heated drops and manifolds. 12 CORPORATE TRAINING AND PLANNING

EXTERNALLY HEATED HOT RUNNER Externally heated hot runner channels have the lowest pressure drop of any runner system (because there is no heater obstructing flow and all the plastic is in molten state). They are better for colour changes none of the plastic in the runner system freezes. There are no places for material to hang up and degrade, so externally heated systems are good for thermally sensitive materials. 13 CORPORATE TRAINING AND PLANNING

INTERNALLY HEATED RUNNER SYSTEM Internally heated runner systems require higher molding pressures, and color changes are very difficult. There are many places for material to hang up and degrade, so thermally sensitive materials should not be used. Internally heated drops offer better gate tip control. It separate runner heat from the mold because an insulating frozen layer is formed against the steel wall on the inside of the flow channel. 14 CORPORATE TRAINING AND PLANNING

INTERNALLY HEATED CORE ROD SECONDARY NOZZLE Fig: 5.4 15 CORPORATE TRAINING AND PLANNING

DESIGN CONSIDERATION FOR HOT RUNNER MOULD Insert plug close off manifold bores should be smooth. Runner diameters should impart shear stress not more than 1 percent of the resin’s tensile strength. The pressure drop from sprue bushing to tip should not be more than 25 percent of the maximum plastic fill pressure, with the resulting temperature increase remaining as close to the desired melt as possible. A runner volume of 25 percent of the part volume, and a shear rate of about 1000 sec-1, are good Sufficient heating elements should be incorporated so that the hot-runner unit heats quickly to the required moulding temperature from cold. 16 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING .   Sufficient heat energy must be supplied to the hot-runner unit it replaces conduction, convection and radiation heat losses.   To ensure that the temperature of the melt in the flow-way is maintained without either hot or cold regions, careful location of the heating elements is essential.    Considerable production time may be lost if a heater fails. Thought must be given therefore to choice of heating element; its location and the facilities for. removing it. 17 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING The layout of the wiring system should be neat and easily traceable.   Heating element wires, which are subject to, heat or abrasion attack should be protected. Use manufacturer’s recommended clearances when fitting heating elements of the cartridge type. Flat-type heating elements and induction heating elements should be completely enclosed within the unit for maximum efficiency. 18 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING The hot-runner unit must be insulated from the rest of the mould structure. For many materials, close control of the temperature of the melt is vital. Hence Careful consideration to be made for the location of thermocouples. To minimize degradation, color-changing and material-changing problems the melt flow-way must be as streamlined as possible, without sharp corners, ledges or other stagnation points which tend to hold back the polymer melt for extended periods. 19 CORPORATE TRAINING AND PLANNING

APPLICATIONS OF HOT RUNNER MOULD It allows for the pin gating of mouldings on multi-impression types of mould It allows for multi-point gating on single-impression and multi-impression mould It allows for side or film gating of large mouldings. It permits the semi-runnerless design to be adopted, where small groups of impressions are fed from secondary sprues. 20 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING THE MANIFOLD BLOCK Rectangular Manifold Block Circular manifold block 21 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig:5.5 Fig:5.6 22 CORPORATE TRAINING AND PLANNING

RECTANGULAR MANIFOLD BLOCK Fig:5.7 Fig:5.8 Fig:5.8 Fig:5.9 23 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING THE MELT-FLOW-WAY Fig: 5.10 24 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING RUNNER PLUG It is made from stainless steel for plugs in the flow path of hot runner system to direct the plasticized materials. It has larger thermal expansion than the manifold material. As the manifold is heated to operating temperature, the stainless plugs will expand at a greater rate making the possibility of leakage impossible. 25 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING TYPES OF NOZZLES Extended nozzle 2. Barb nozzle 3. Antechamber nozzle 26 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING 1.EXTENDED NOZZLE On the extended nozzle a resistance type band heater is provided which is controlled by means of thermocouple. To minimize the transfer of heat from the heated nozzle to the mould, a circumferential clearance of at least 7mm must be provided between the two parts. The main advantage of this nozzle is to minimize the length of the sprue gate as short as possible. 27 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig:5.11 EXTENDED NOZZLE 28 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING 2.BARB NOZZLE This type of nozzle is used to minimize the blemish on the component at the gate point. The plastic material flows through to the nozzle, sprue and gate. After solidification, the sprue is pulled from the sprue bush by the barb of the nozzle. 29 Fig:5.12 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING 3.ANTECHAMBER NOZZLE It is termed as hot well design, a small mass of plastic material is retained in the antechamber which insulates the central core of plastic material. The plastic material remains fluid to allow it to pass intermittently through the antechamber into the impression. This type of nozzle is used for moulding thin-walled components. 30 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING INSERT ANTECHAMBER 31 CORPORATE TRAINING AND PLANNING Fig:5.13

INSULATED RUNNER MOULD In this type of mould the melt flows from standard or extended nozzle into a large diameter runner via the reverse taper sprue and gate. The outer layer of the melt solidifies against the cold runner wall which forms an insulating shell, while the centre core of the material retain in the molten state. The outer layer of runner acts as an insulating media and avoids heat loss from the polymer melt to the mould. 32 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING Fig:5.14 33 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING EXPANSION PROBLEMS The hot-runner unit mould is that metals expand when heated. The manifold block increases in all three dimensions when the temperature is increased. The distance between the centers of the secondary nozzles increases with respect to the ‘fixed’ distance between the centers of the impressions machined in the cavity plate. When designing the hot-runner mould, allowance must be made for this expansion to ensure that the centerlines are in line during production 34 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING EXPANSION PROBLEMS Fig:5.15 35 CORPORATE TRAINING AND PLANNING

CORPORATE TRAINING AND PLANNING NOZZLE LENGTH 200 250 300 48 mm 68 mm 0.13 0.20 0.17 0.21 0.30 The equation for calculating expansion is as follows: e = L X  X  T Where e = expansion (mm or in) L = length dimension (mm or in)  = Coefficient of thermal expansion (mm/mm C or in / inC)  T = increase in temperature ( C) 36 CORPORATE TRAINING AND PLANNING

DESIGN OF HOT RUNNER MOULD FOR CAP CORPORATE TRAINING AND PLANNING

HOT RUNNER MOULD FOR CAP SEAL CORPORATE TRAINING AND PLANNING

THREE PLATE HOT RUNNER MOULD FOR CAP CORPORATE TRAINING AND PLANNING

THREE PLATE HOT RUNNER MOULD FOR LEAD FRAME CORPORATE TRAINING AND PLANNING

UNSCREWING HOT RUNNER MOULD FOR CAP COMPONENT CORPORATE TRAINING AND PLANNING