Brief Introduction on DESMA Pharmaceutical Halobutyl Rubber Bottle Stoppers Injection Molding Machine
--Aoxiang Pharmaceutical Packing Co. Ltd, Zhengzhou City, Henan Province, 452483

Abstract: This paper primarily introduced the structure, technical parameters, related techniques for producing Halobutyl Rubber Stoppers, and performance advantages of Germany DESMA rubber injection molding machines.
Keywords: Germany DESMA Rubber Injection Molding Machine, Halobutyl Rubber Stoppers, Performance Advantage

Aoxiang, a China manufacturer of pharmaceutical Halobutyl Rubber Stoppers, introduced Germany DESMA rubber injection molding presses in 1997. Based on those years' experience, we now give a brief introduction on the machine.

Main components of DESMA rubber stoppers injection molding press:
plasticizing and injection equipment, mold clamping mechanism, hydraulic power system, temperature control unit and operation monitoring system etc..

1. Plasticizing and injection equipment
The equipment is mainly used for feeding gross rubber into molds and then plasticizing the compound.
(1) Gross rubber is draw into molds by screws; and then injected into injection barrel by piston. The non-return device in the piston can prevent reflux of the gross rubber.
(2) The power needed is provided by hydraulic system.
(3) Consisting: machine frame, guide pillar, hydraulic injection system, hydraulic motor, injection barrel, transverse barrel, injection mouth and vertical shaft etc.; all components are connected to each other by the vertical shaft.
(4) Features of the system: ①equipped with non-return valve; ②compatible with hot runner technology; ③short injection tunnel helps reducing pressure losing; ④retractable injection mouth improved the machine stability.
2. Mold clamping mechanism
(1) Mold clamping mechanism is primarily used to guarantee the precise open and close of moulding system.
(2) Consisting: mold clamping plate, heating plate, vertical shaft, movable plate, pressure plate, mold clamping barrel, transverse barrel etc..
(3) Transverse barrel is used for opening and closing the mould.
(4) Transverse barrel is installed on the pressure plate and movable plate; during the injection forming process, the clamp force for opening moulds comes from mold clamping barrel. And the barrel is powered by hydraulic system.
3. Hydraulic power system
(1) The system is mainly used for providing power to each related system of our rubber injection molding press.
(2) Consisting: main motor, pressure-regulation pump, oil cooler, cooling water system, oil filter and sensor etc..
4. Temperature control unit
(1) Temperature control scope: feeding area, screw barrel, injection barrel, cold runner, heating plate etc.; and their temperatures are all controlled by exclusive temperature adjusting circuits.
(2) The temp. of screw barrel, injection barrel and cold runner are controlled by 5 exclusive temp. control elements.
(3) Heating and cooling medium: oil or water;
(4) The heating platens is heated by several rows of heating wires. There is a T type incision on the heating plate, so the mold can be fixed onto heating plate by T screws and nuts.
5. Operation monitoring system
(1) The operation monitoring system is connected by cables and is installed in the switch cabinet.
(2) The machine is controlled by DRC-2000 control system.
(3) Industrial computers are adopted to control the machine's operation or parameter setting. The set values can be input through the keyboard of OPV.
(4) High safety operation is guaranteed by the photoelectric baffle.

Technical parameters of DESMA rubber stoppers injection molding press:
1. Production Process:
Mold matching--Injection delaying--Injection--Pressure keeping--Curing--Mold opening--Lift off the rubber film.
Note: During the curing process, rubber stock has been plasticized for the next period production.
2. Parameters comparison between DESMAD968.400T & DESMA968.500T rubber injection molding press:

Item	Unit	D968.400T	D968.500T
Piston Diameter	mm	105	115
Injection Pressure	bar	280	280
Rubber Injection Amount	cm3	3300	5000
Piston Stroke	mm	390	490
Injection Force	kN	1790	2093
Screw Diameter	mm	55	65
Length/Diameter Ratio of Screw	L:D	10:1	10:1
Rotation Speed of Screw	Umin	20--200	20--160
Heating Power	kw	2×4.5	3×4.5
Press Force of Injection Device	kN	153	153
Mold Clamping System		Hydraulic/Mechanical	Hydraulic/Mechanical
Mold Clamping Force	kN	4000	5600
Mold Opening Stroke	mm	600	650
Min. Mold Thickness	mm	180	180
Max. Distance between Heating Plates	mm	1110	1190
Distance between Vertical Shafts	mm	820×593	944×677
Oil Tank Capacity	L	300	300
Total Load	kw	70	70

Performance advantages of DESMA rubber Stoppers injection molding press:
1. DESMA rubber injection molding press skipped the gross rubber preforming process, which can avoid quality problems of gross rubber during preforming process.
2. High production efficiency:
DESMA injection molding press adopted high temperature high speed curing technology: production speed: 3-4 min under temperature of 195±3℃;
Other plate vulcanization machine: 4-8 min under temperature of 170-180℃.
3. High automation, zero waste molding and high output capacity.
4. High precision:
the thickness precision of produced Halobutyl Rubber Stoppers crown: ±0.2mm;
and as a result, the press is especially suitable for producing infusion Stoppers and freeze-dry closures.
5. Same vulcanization degree for the internal and external of the rubber Stoppers; good rubber density.

Requirements:
1. High quality and high precision molds is required;
2. Rubber stock requirement: low mooney viscosity; long scorch time;

Conclusions
DESMA rubber injection molding machines are good choices for producing Halobutyl Rubber Stoppers (rubber closures). They can highly improve production efficiency and closure quality.

References:
1. Instructions on DESMA Rubber Injection Molding Press
2. Pharmaceutical Packaging, China Pharmaceutical Packaging Association
3. Technological Principle of Rubber Molding, Bencheng Deng, Kuijiang Ji