How to Check the Barrel and Ring Wearing of Injection Molding Machine The following phenomenon may possibly be encountered depending on the type of resin used in operation for a long period of time. (1) The cushion amount fluctuates. (2) Sink marks cannot be eliminated. (3) The absolute value of the cushion amount becomes lessened. In this case, the barrel or check ring may have been worn. To inspect the wearing state of the barrel or check ring, it is preferable to actually measure the sizes of the barrel or check ring. In the actual case, however, checking by means of double shots is available to simply judge the wearing of the barrel or check ring as described below. * Double shot is to conduct injection again without mold opening or product take-out after injecting charged melt into the mold cavity. The screw advances little even if double shots are carried out. The screw keeps advancing when double shots are carried out. [Recommended conditions] Holding time (TRH1) = 5 s Injection time = 5 s Holding pressure (PH1) = 100
Read more →Heater Maintenance and Inspection of Injection Molding Machines Band heaters or aluminum-cast heaters are usually used for the barrel. Most of our injection molding machines use the former, band heaters in which Nichrome wire is placed between stainless sheets and insulated with mica. Follow the procedure below for the maintenance and inspection of the heaters. 1) Heater band failure is mainly caused by improper tightening. The watt density of heater is about 3 ~ 5 W/cm2. A less contacting area with the barrel results in self-heating and eventually in disconnection. Thus retighten heaters while hot at least once a month. 2) When retightening the above, also inspect screws of heater wiring (such as screws for the terminal box, contactors, etc.) for looseness. 3) Heaters should show a few megaohms or more of insulation resistance after being heated once. Insulation resistance of less than one megaohm (1MΩ) will adversely affect the human body due to leak current. Investigate the cause of the problem and replace heaters if no cause is found. 4) When retightening the above, also inspect thermocouples for secure
Read more →Forced Grease Mode in Injection Molding Machines The forced grease mode function is to exhaust air when the air entering in a grease line is observed even after air venting work at grease cartridge replacement (the injection machine does not move smoothly or grease cannot reach each greasing point) or to change grease inside the grease line after a long downtime of the injection machine. Execution of forced greasing effectively prevents damages on ball screws, link pins or linear guides, or motor load increasing. (1) Operation The greasing pump operates by forced grease mode and supplies grease to each valve. After the pump pressure reaches to 5MPa (725psi), the greasing pump outputs pump stop signal and stop operation. Then each valve discharges grease to greasing points and the pump starts operation again after one minute. The pump repeats that procedure five times. (Repeat number setting: C106) (2) Performance circuit diagram The performance circuit diagram of forced greasing is as follows. Operation procedure of forced grease mode: 1) Press [SERVO] of the PREPARATION button on the operation controller to turn off
Read more →How to Replace the Grease Cartridge in Injection Molding Machines When grease is getting short in the grease cartridge or an alarming comment [GREASE IS SHORT] is activated, replace the grease cartridge by following the procedure below. FS-2 (by LUBE) that is for former greasing pump can not be used for P-107 because of differences in pump discharge pressure and grease consistency. FS-2, if used, may cause pump breakage or pipe clogging. [New pump] Model: P-107 (discharge pressure: 5 MPa) Recommended grease: LHL-X100 (*FS-2 can not be used.) [Former pump] Model: EGM-10T(MP)-4-7C (discharge pressure: 10 MPa) Recommended grease: FS-2 or LHL-X100 (* LHL-X100 can be used for new pump and former pump.) 1) Turn counterclockwise and remove the clear cover from the pump. 2) Turn counterclockwise and remove the empty cartridge from the pump. 3) Insert new cartridge to the pump together with the inside plug, and turn clockwise and set to the pump. Exercise care not to enter air or foreign matter into the inside. (The inside plug gets torn when new cartridge is inserted to the pump.) 4)
Read more →How to Inspect Lubrication System of Injection Molding Machines Inspect the lubrication status of the respective unit for the following points. (1) Check if lubrication is insufficient. (2) Check if grease is discolored, fouled or solidified. (3) Check if refuse or foreign matter is caught. (4) Check the sliding surface for scratches. When grease on the ball screw is fouled or catching foreign matter, wipe off the grease with a piece of clean cloth. Never use a solvent for this purpose. Using a solvent cuts oil film while possibly shortening ball screw life. When the mold has not been changed for a long time, press OPEN and CLOSE of the DIE HEIGHT button to open and close the platen one time for the purpose of lubricating the mold thickness setter. At this time move the platen for the full stroke of DIE HEIGHT. The following portions are equipped with automatic greasing circuits. Be sure to use high load-resistant high-performance grease recommended by us for the automatic greasing circuit. 1) Injection ball screw 2) Injection linear guide 3) Ball screw for
Read more →How to check Belt Dislocating of All-electric Injection Molding Machines Follow the procedure below to check timing belt dislocating on respective units (clamp unit, ejection device, injection drive unit, charge drive unit). 1) Move respective drive units on their stroke to [0] mm point. 2) Check if white marks on the pulley and belt meet, both on the drive and driven sides. By TOSHIBA MACHINE CO.,LTD.
Read more →How to Inspect Injection Molding Machines by Eye Timing belt and pulley require earlier replacement if illustrated as below. Please contact our service department. (1) Wearing on the belt tooth surface (Change limit: Approx. half the face width) (2) Crack on the root of the tooth of belt (Change limit: Approx. half the face width) (3) Crack on belt back face (Change limit: Approx. one-third of thickness at the root of the tooth) (4) Swelling of the belt by oil adhering (5) Wearing of the pulley tooth surface (Change limit: Wearing by 0.5~1 mm) [0.020~0.039 in] By TOSHIBA MACHINE CO.,LTD.
Read more →Inspection Method of Belt Tension in Injection Molding Machines Check by Tension Meter Follow the procedure below to check the belt tension of respective units (clamp unit, ejection device, injection drive unit, charge drive unit). 1) See [Appendix] and input span length, belt width and unit mass of the belt to a belt tension meter. 2) Give a light shock to the checkpoint of the belt by using a hammer. 3) Set a tension meter close to the vibrating belt to measure its tension. 4) Belt tension can be judged to be proper if the belt tension is within the target setting range. Check by Press Force Follow the procedure below to check belt tension of respective units (clamp unit, ejectiondevice, injection drive unit, charge drive unit). 1) See [Appendix] and check amount of deflection and press force of the belt. 2) Check actual press force when pushing the check point of the belt until the belt gets the amount of deflection on the list. 3) Belt tension can be judged to be proper if the press force is within
Read more →How to Check the Belt Tension of All-electric Injection Molding Machine Belt Tension Checking Point on Clamp Unit of All-electric Injection Molding Machine Belt Tension Checking Point on Ejection device of All-electric Injection Molding Machine Belt Tension Checking Point in injection drive unit of All-electric Injection Molding Machine Belt Tension Checking Point in charge drive unit of All-electric Injection Molding Machine By TOSHIBA MACHINE CO.,LTD.
Read more →How to Check Nozzle Alignment on Injection Molding Machines Check the nozzle center when changing the mold. In the case of a mold without locating ring especially, securely check the nozzle center. Misalignment of the nozzle center may cause resin leakage or mold damage. Follow the procedure below to adjust nozzle alignment. 1) After mold mounting, continuously press [ADVANCE] of the NOZZLE button to touch the nozzle tip to the mold for nozzle misalignment check. (At this time insert a piece of paper between the nozzle tip and mold to ease misalignment direction.) 2) Press [RETRACT] of the NOZZLE button to move the nozzle to the retract limit. If the nozzle center shifts vertically, loosen the clamp bolt fixing the injection unit to the base and use adjust bolt to adjust the height of the injection unit and secure vertical alignment. 3) If the nozzle center further shifts horizontally, use the horizontal adjust bolt equipped on the operation to adjust the horizontal positioning of the injection unit. 4) After adjusting tighten the clamp bolt. * Refer to the instruction manual
Read more →How To Replace Heater Fuse in Injection Molding Machines Since a triode AC switch (semiconductor) is used for the solid-state relay in the heater control circuit, a fuse for semiconductor protection (instantaneously melting fuse) is used to prevent overcurrent. The fuse, when required, must always be replaced with the same type and rating of the fuse. Note that a normal fuse cannot protect the solid-state relay. Even if an instantaneously melting fuse is used, repeated fuse blowing due to short-circuits, etc. will deteriorate the semiconductor, possibly causing damage to the solid-state relay. Therefore, short-circuiting should be minimized. There are instantaneously melting fuses in the Injection box of non-operation side. By TOSHIBA MACHINE CO.,LTD.
Read more →How To Replace the Barrel in Injection Molding Machine Replace the barrel by following the procedure below. 1) Swivel the injection unit. 2) Withdraw the screw by referring to the previous section. 3) Remove heater cover, thermocouples, and heater cables. 4) Remove the barrel set bolts with the barrel suspended by wires hooked on the eye bolts. 5) Draw the barrel forward and remove it while suspending. 6) Tighten clamp bolts After replacing screw and barrel, return injection unit and base to machine-center. Refer to the instruction manual “Appendix”, to tighten clamp bolts with proper torque. The clamp bolt tighten with excessive torque causes offset of nozzle-center. By TOSHIBA MACHINE CO.,LTD. Feel Free to Contact Us if Any Questions
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