Standard Components For Plastic Mold 2021

PRODUCT DATA

■ Selection Method for Straight Core Pins with Tip Process

■ Comparison of Guaranteed Range of Shaft Diameter Precision between Ejector Pins and Core Pins

Codes for Core Pins with Tip Process

Ejector pins

Core pins

CP □ L □ CP □ JL □ (JIS head standard –0.01 CP □ BL □ CP □ JBL □ (JIS head standard –0.01

Shaft diameter (D) selection type Shaft diameter (P) designation type

–0.02 SKD61 equivalent only)

b 1 (Range of guaranteed shaft diameter precision)

X 1

b 1 (Range of guaranteed shaft diameter precision)

X 1

–0.02 SKD61 equivalent only)

Material/Tolerance codes

Tip process code

Shape Tip process code D P.335 – P.345

Group

Standard

Precision Extra precision

0 –0.005

–0.01 –0.02

0 –0.005

0 –0.003

Shaft diameter(D or P)

C (C chamfered)

Length (L) *

0 –0.02

0 –0.01

Guaranteed range of shaft–diameter precision b 1 ≧ L–X 1 max.

X 1 dimensions

P 1 precision

Shaft diameter (P) precision

P 1 Precision

Shaft diameter precision

Ejector pins X 1 max.

Core pins X 1 max. L ＜ 10 L ≧ 10 Standard T(TC) + 1.5 T(TC) + 4

SKH51

T4 (4mm) JIS (4/6/8mm) T10 (10mm)

30 35 40

Shaft diameter Shaft diameter Shaft diameter

0 –0.1

0 –0.002 0 –0.005

0 –0.05 0 –0.05 –0.01 –0.06

0 –0.003 P 1

SKD61

–

L ≦ 150

P 1

G (Cone)

0 –0.1

0 –0.005 P 1

NAK80

–

P 1

E X1max. varies depending on the L dimension. For details, refer to D P.7

Precision Extra precision

T(TC) + 1 T(TC) + 2

L > 150

–0.01 –0.02

–0.01 –0.1

–0.01 –0.02 P 1

DH2F

–

P 1

SUS440C

–

T (Tapered)

■ Designation Method and Precision of Key Flat Cutting of Ejector Pins and Core Pins ● Method of key flat cutting

MAS1C

–

(Prehardened)

Two flats ( different dimensions )

–

Key flat cutting

Two flats ( parallel )

Two flats ( right angled )

Two flats ( angled )

Three flats ( at 120° )

R (R chamfered)

Single flat

Three flats Four flats

(Hardening steel)

PROVA400 (Prehardened)

–

KC VKC

WKC VWC

KAC KBC

PROVA400 (Hardening steel) – e ＊ The tolerance values for L dimension are representative ones. The tolerance range varies depending on the shape selected. For details, refer to the Catalog page of each product. RH QH –

Code

RKC

DKC

SKC

KGC

KTC

0 ° AG °± 0.5

120 °

(Spherical)

120 °

Alterations

e ＊ Precision/extra precision is R specied, Standard is (RC) processing as shown in gure on the right.

120 °

WKC / VWC

SKC

RKC

KC/VKC

KAC

KBC

KGC

DKC

KTC

Shaft diameter 2 ≦ KAC KAC ＜ KBC ＜

Range of designation

Head diameter 2

Shaft diameter 2

Head diameter 2

≦ KC VKC

≦ WKC VWC

＜

≦ RKC ＜

≦ DKC ＜

≦ SKC ＜

≦ KGC ＜

≦ KTC ＜

Head diameter 2

■ Finishing of tips and edges

①

②

Specify according to shaft diameter

Specify as free dimension (outside the shaft diameter)

When designated according to shaft diameter , in order to designate the shaft diameter × –1 2 , Dimensions can be specified in the following units for each shaft diameter type.

When designated using free dimensions , Designation is only in 0.1mm increments

When ejector pins and core pins are processed to determine the total length, fine, processing burring about 0.02–0.05mm (reference values) in length occurs at the edge of the tip. When this burring is removed, a slight sag results.

Shaft diameter selection type

0.05mm increments 0.005mm increments 0.0025mm increments 0.0005mm increments

Shaft diameter designation (0.01mm increments) type Shaft diameter designation (0.005mm increments) type Shaft diameter designation (0.001mm increments) type

KC ＝

KC ＞

shaft diameter

MISUMI does not process the tip in order to prevent sagging.

The allowable sag R depends on a variety of conditions (such as the particular mold being used precision of mold, characteristics of the formed object, shape, resin type). For this reason, the sag R caused by deburring may be an issue. Use an oilstone, sandpaper, cloth, etc. to remove the burring according the precision control standards on your design drawing of the mold being used.

● Precision of key flat cutting

① When key flat cutting is designated according to shaft diameter. Category Key flat cutting tolerance Ejector pins 0 –0.1 Ejector pins alterations VKC/VWC/VAK/VAW 0 –0.02 Core pin shaft diameter tolerance 0 –0.003 0 –0.01 Core pin shaft diameter tolerance 0 –0.005 Core pin shaft diameter tolerance –0.01 –0.02

② When designated with free dimensions Category

Key flat cutting tolerance

0 –0.1

Ejector pins

On general purpose machinery, it is common to use slight chamfering (about C0.1–0.3), but as the tips of the ejector pin and core pin come in contact with the formed object, chamfering is generally not carried out or kept to a minimum.

Ejector pins alterations VKC/VWC Core pin shaft diameter tolerance 0 –0.003 Core pin shaft diameter tolerance 0 –0.005 Core pin shaft diameter tolerance –0.01 –0.02

0 –0.02

About processing burring: W hen cutting (with a blade) or grinding (with a grinding stone) steel, small splinter shaped burrs occur on the edge of the processed surface. For example, just like splinters occur when wood is cut with a saw, similar small splinters occur when processing metal. These splinters are called burrs. In general, the size of the burrs is smaller for harder materials. On the other hand, the pieces of material that melts and is caught in gaps during casting, die–casting, and molding of plastics are called flash.

0 –0.01

In English, the burrs caused in processing are called BURRs, while those cause in molding are called FLASH, or FIN. Reference: Zukai Kikai Yougo Jiten (Illustrated Dictionary of Machinery), THE NIKKAN KOGYO SHIMBUM, LTD.

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