Heat transfer simulation for decision making in plastic injection mold design

Gruber, Piery Antonio; de Miranda, Diego Alves

doi:10.1590/0104-1428.08319

Piery Antonio Gruber

Departamento de Engenharia Mecânica, Universidade da Região de Joinville – UNIVILLE, São Bento do Sul, SC, Brasil

Diego Alves de Miranda ^* * diegoalves_klx@hotmail.com

Departamento de Engenharia Mecânica, Universidade da Região de Joinville – UNIVILLE, São Bento do Sul, SC, Brasil

http://orcid.org/0000-0002-9774-4705

* diegoalves_klx@hotmail.com

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Figure 1
Polypropylene Lid. (a) Injected; (b) in CAD.

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Figure 2
Lid injection mold: (a) isometric view; (b) demonstration of the mold males; (c) floating plate opening (plate numbering); (d) isometric view demonstrating mold opening; (e) assembled mold.

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Figure 3
Gate location in lid mold.

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Figure 4
Mold cooling system: (a) plate number 2; (b) plate number 3; (c) plate number 6.

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Figure 3
Gate location in lid mold.

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Figure 4
Mold cooling system: (a) plate number 2; (b) plate number 3; (c) plate number 6.

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Figure 5
Validation simulation performed on the cover with a “U” type cooling channel.

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Figure 6
Proposed modifications to the lid mold cooling system. (a) “Z” type circuit; (b) “Rectangle” type circuit; (c) “Helical” type circuit.

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Figure 7
Qualitative validation under process conditions: (a) step a; (b) step b; (c) step c; (d) step d; (e) step e; (f) step f.

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Figure 8
Cooling time variation.

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Figure 9
Cover temperature after solidification in each type of cooling system.

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Figure 10
Mold temperature after solidification in each type of cooling system.

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Table 1
Processing parameters for simulation validation.

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Table 2
The filling volume of the samples and the corresponding standard deviation.

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Table 3
Qualitative validation under process conditions: (a) step a; (b) step b; (c) step c; (d) step d; (e) step e; (f) step f.

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Table 4
Estimated production for each cooling system.

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Table 5
Results of values for payback calculations.

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(2)

(3)

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(12)

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(16)

Step	P₀ (bar)	T₀ (°C)	T_L (°C)
a	30	210	35
b	50	210	35
c	60	210	35
d	70	210	35
e	85	210	35
f	95	210	35

	Fill Volume (%)
Samples	a	b	c	d	e	f
1	31.57	52.64	63.14	73.64	89.42	100.0
2	31.33	52.58	63.24	73.54	89.28	99.90
3	31.27	52.48	63.04	73.56	89.26	99.83
4	31.67	52.78	63.00	73.74	89.22	99.82
5	31.72	52.85	62.97	73.70	89.52	100.0
6	31.76	52.50	62.94	73.58	89.48	99.85
7	31.82	52.45	63.35	73.44	89.52	100.0
8	31.28	52.35	63.19	73.84	89.6	99.81
9	31.25	52.78	62.98	73.82	89.48	99.92
10	31.15	52.63	63.25	73.81	89.50	99.75
σ (%) ±	0.226	0.132	0.124	0.114	0.106	0.080

Step	Fv (%)	σ (%)	Fvs (%)	Eft (s)	tps (s)	Sft (s)	trs (s)	Efct (ºC)	Sfct (°C)
a	31.57	± 0.226	35.0	0.70	0.47	3.0	3.04	90.55	92.09
b	52.64	± 0.132	55.0	1.20	1.09	5.0	5.12	93.75	95.74
c	63.14	± 0.124	65.0	1.30	1.18	6.5	6.91	96.55	98.45
d	73.64	± 0.114	75.0	1.60	1.48	7.5	7.74	97.70	99.40
e	89.42	± 0.106	90.0	1.75	1.63	8.0	8.09	98.62	100.14
f	100.0	± 0.080	100.0	1.90	1.79	9.5	9.67	99.80	101.68

Cooling system	Cooling Time (s)	Total cycle (s)	Quantity of Parts/h	Quantity of Parts/day	Quantity of Parts/Month	Quantity of Parts/Year
“U”	15.7	22.0	1,300	31,200	487,500	5,600,000
“Z”	15.6	21.9	1,315	31,560	493,000	5,624,000
Retangular	14.4	20.7	1,390	33,360	521,250	5,910,000
Helical	13.2	19.5	1,475	35,400	553,000	6,200,000

Cooling system	“Z”	Rectangular	Helical
Inv	R$6,869.00	R$8,952.20	R$14,159.60
GR	R$2,800.00	R$37,200.00	R$72,000.00
d	R$ 555,75	R$729.35	R$1,163.00
TR	R$2,444.25	R$36,670.35	R$71,037.00
Income Tax	R$262.26	R$3,934.76	R$7,622.27
AS	R$2,537.73	R$33,265.24	R$64,377.73
Present value	R$15,720.16	R$206,057.30	R$398,779.10
NPV	R$8,851.16	R$197,105.10	R$384,619.50
Pb	42 Months	3.5 Months	3 Months

[1] * diegoalves_klx@hotmail.com

Brasil

Brasil

Heat transfer simulation for decision making in plastic injection mold design

Abstract