注塑机能耗的测量

Measuring energy consumption in

injection moulding machines

Tat Ming Technology Co. Ltd.

Kevin Tong

Nov 2013

1

Test standards

• European std （2013.1）

– Euromap 60.1

– Euromap 60.2

• Chinese std（2009）

– Industrial std

• Hong Kong std（2013）

– HKPMA std

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Why energy eff. test std？

• Many factors affect energy consumption

• Factors

– Machine size

– Product

• Material

• Shot weight

• Wall thickness

– Cycle time

• Perf. test according to std. to hold factors constant

• So comparison of brands and design makes sense

• Result is unit energy consumption or efficiency class

Use std molds？

• There are pros and cons

• Standard molds

– Reduce # of param. spec.（pros & cons）

– Limited # of molds to cover a big range of m/c（cons）

– Used by industrial std

– Used by HKPMA std

• No molds specified

– Euromap 60.1

• Any mold could be used

– Euromap 60.2

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Industrial std

• Proposed by a group of manufacturers headed by Haitian in Oct 2009

• Machines are class. by shot vol.

– Class upper limit = 3*lower limit

– Geometric series

– Each class uses its own std mold

– Cold runner molds

– Circular disks with sprues

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5 molds

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Mold spec

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Other spec

• PS material

– Undried, not pre-heated

– Specific gravity 1.05 g/cm3,

– MFR(200,5) = 4.5 ～ 5.5 cm3/10 min

– Barrel temperature 250±10℃

• Room temperature 15℃～35℃

• Shot vol ＞3888 cm3 or when std molds could not be used

– Use mold spec. by manufacturer or user

– Undried and not pre-heated PP

– Shot weight 1/4～3/4 of machine shot weight

– Include sprue weight if there is sprue

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Indicator and eff. class

• Indicator is kWh per kg of PS used

• Make 50 shots

• 6 efficiency classes

• Classes 1 &2 are energ.

efficient classes

• Arithmetic series

– Class size 0.15 kWh/kg

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Std characteristics

• #3 mold covers 145 - 432 cc shot volume range

• Corr. to m/c w/ clamping force 75 – 180 tons

• Servodrive machines could reach class 1

• Variable displacement pump m/c could reach class 2

• Small machines have higher kWh/kg

– Many shots to make 1 kg, low plasticizing capacity

• Big machines have lower kWh/kg

• Includes peripheral equipment energy consumption

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kWh/kg

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Machine size

• Shot volume range 16 - 3888 cc

• Clamping force range about 20 – 700 tons

• Only 5 classes of machine size

• Each with its own mold

• Class upper limit is 3 times lower limit

• Class range is big – About 75 – 180 tons for #3 mold

• So not too many molds are needed to cover range

• Big machine has a high kWh/h, but a low kWh/kg

HKPMA std

• 5 molds

• Shot vol. range 85 - 2719 cc

• 5 classes of machines, delimited by shot vol

– High limit is double low limit

– Geometric series

• PP material used

• 220° C barrel temperature

• More parameters spec vs industrial std

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EUROMAP 60.1 & 60.2

• EUROMAP is an assoc. of European plastic

equipment manufacturers

• Most well-known for its CE safety std

• EUROMAP 60.1 and 60.2 eff. test std

announced in Jan 2013

• Euromap 60.1 does not spec molds

• Euromap 60.2 uses any molds

Euromap 60.1

• PP material used

– Not dried, not pre-heated

– MFR(230℃ ,2.16 kg) = 20 ～ 25 g/10 min

– Barrel temp. 220℃ ±3℃，within 30 min.

• Room temp. < 30℃

• Peripheral equip. excluded

• All shots are made consecutively

• Not shorter than 10 min. & not fewer than 5 shots. For screw diameter >= 80 mm, 3 shots are OK

• Defined idle state and idle power

• Is an IMM eff. test, classify IMM into 10 classes

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2 cycles

• Cycle I , standard IMM

• Cycle II, high injection speed IMM

• For each cycle, clamping and injection

parameters are specified

– Same clamping parameters for both

– Diff. inj., plast., back prs. and cooling parameters

• Adjust. nozzle to generate injection pressure

• Clamping block to generate clamping force 16

10 efficiency classes

等级 比能耗kWh/kg 的几何数列

1 >1.50

2 ≤1.50 1.50

3 ≤1.20 1.199

4 ≤0.96 0.958

5 ≤0.77 0.766

6 ≤0.61 0.612

7 ≤0.49 0.489

8 ≤0.39 0.391

9 ≤0.31 0.313

10 ≤0.25 0.25 17

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Class boundaries

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Indication of results

• + means low idle power

– Idle power ≤ 1 kW for m/c below 400 tons

– Idle power ≤ 3 kW for m/c equal or above 400 tons

• On a std machine test, the specific energy

consumption is 0.8 kWh/kg, idle power is 0.9

kW, Euromap 60.1 indication is (CycleⅠ) eff.

class 4+

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Euromap 60.2

• Uses any mold

• Not a test of IMM, no efficiency classes

• Measures a particular mold on a particular

IMM with certain peripheral equipments

• 5 blocks of equipment, meas. their powers sep.

– IMM motion, mold motion, barrel heaters

– Peripheral equipment

• Cyclic（e.g. robot）。 Non-cyclic（e.g. hopper dryer)

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Detailed report

• IMM information

• Product information

• Temperature

• Energy consumption

- Specific energy consumption kWh/kg

- Avg. power（3 – 5 blocks measured separately）

- Idle power

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kWh is a big unit

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Insufficient resolution

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• Home power meter has 0.1 kWh resolution

• At 0.4 kWh/kg, needs 25 kg resin to use up 10

kWh, then resolution is 1%

• For a small machine, 50 shots does not use up

25 kg of resin

– Resolution in doubt

– Can tell two IMM’s apart？

• Digital power meter has a 0.001 kWh resolution

Digital power meter

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IMM PLC + Dig. p. meter

• Automate the measure.

– Fast, accurate, error-free

– Integral # of cycles

– Separate meas. of motion, heat,

peripheral equipment

– Can use any std

– Can be a tool for optimization

– An option in Tat Ming machines

• Stand-alone unit

– Moveable, can measure all IMM in the factory 25

Current transformers

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Machine ener. consump.

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Heater energ. consump.

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Para. affect ener. cons. 1

• Slow plasticizing

– Finish plast. w/ cooling

– Suitable for var. disp.

pump

• Fast plasticizing

– Fastest plast., then stop

– Suitable for servodrive

• Back pressure

– High bp = high energ. con.

– Find min. bp possible

• High temperature

– Higher heat loss

– Longer cycle time

– Lower screw torque

• Short cycle time

– Acc. & dec. waste energ.

– Vibr. reduces m/c

reliability

– Reduces heat loss

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Para. affect ener. cons. 2

• Clamping force

– As low as possible

– Without flashing

• Opening stroke

– As short as possible

• Injection pressure

– As low as possible

– While completely filled

• Ejection force

– As low as possible

– Don’t hit bottom

– Push & pull, no springs

– Springs not too stiff

• Ejection count

– As few as possible

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Barrel energ. consump.

• Reduce heat loss

– Convection, highest

– Radiation, smaller

– Conduction at rear zone

• Loss by convection,

radiation

– Prop. to surf. temp.

• Insulation to increase

temperature drop

– Prop. to surf. area

• Induction heating

– Induction cooker princ.

– Heat gen. in barrel mat.

– Fast resp. to set temp.

– Off when set temp.

reached

• Infrared heating

– Avoided contact

resistance

– Big surf. area 31

Barrel temperature

• Barrel cover

– Stainless steel shell

– Insulation mat. in shell

– Epoxy cover on top

• Rising temp. profile

– Set low temp. at rear

zone

– Raise water collar temp.

– Reduces conduction loss

– Reduces temp. override

downstream

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Perip. equip. energ. cons.

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Hong Kong pavil. 3E231

• Green manufacturing

theme

• Energy saving

• Environmental friendly

resins

– Degradable

– Renewable

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