CAT-SET

THREADING

Thread Mill TroubleshooƟng Guide

Problem

Causes

Causes

Thread mill is showing accelerated or excessive wear

Cuƫng edges are chipping

Thread mill is breaking in the first hole of part Thread mill is creaƟng excessive chaƩer Out of round thread is produced

Bell-mouthed thread form (small at boƩom, big at top) Part rejecƟon because of rough flank finish

Steps in thread profile

Gauge difference from part to part

Machine not making correct

paths to create thread profile Control not accepƟng the program

1

1

Incorrect tool selecƟon

2, 3 2, 3

2, 3

2, 3

Incorrect speed and feed selecƟon

Catalog

5

RPM too high RPM too low

4

4

4

5, 19

Machine tool specificaƟons restrict RPMs

7

7

7

7

7

Feed rate too high Feed rate too low

6

Incorrect adjusted feed rate adjustment ra Ɵo Machine tool specificaƟon restricts feed rate Ramp-in is programmed as an axial move Thread mill moved or slipped in its holding device Tool is sƟcking out of the holder too far Runout between thread mill and holder Incorrect coaƟng creaƟng built-up edge

12

Speed and Feed

7, 19

20

20

13 13 13 13

13 13

15 15 15 15

15 15 15

10

10

8, 17

8, 17

Tool

9

9

Helix angle too low

11 11

Excessive thread mill wear

7, 11, 14

7, 11, 14

Excessive tool pressure

16 16 16 16

16

16

Workpiece moving in its fixturing Insufficient coolant pressure or flow

17 17 16 16

16

16 16

Lack of machine rigidity Incorrect number of passes Incorrect program variables

Machine

22

22

18, 26

18, 26

Did not account for X/Y radial moves for tapered threads Incorrect cuƩer compensaƟon variables Helical interpolaƟon opƟon not on machine or turned off Machine tool control is not formaƩed to standard EIA/ASCII/ISO Code

24, 26

23, 26

23, 26

21, 26 21, 26

Programming

25, 26

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