Granted Patent B2

US 12,343,786 · App. 17/836,847 · Granted Jul 1, 2025

Inventors: Michael Ludsteck (Munich, DE); Manuel Guglhör (Benediktbeuren, DE)

Assignee: Atlas Copco IAS GmbH

B21J5/066G05B19/182Y10T29/53383

Abstract

Claims (45)

1. A method for controlling a flow-hole and thread-forming process in which a fastener is driven through a workpiece with a rotation speed (N), a torque (M), and a feed force (F) over a penetration depth (Z), the method comprising:

a) measuring a process parameter (R(t)) of the flow-hole and thread-forming process;

b) determining a smoothed curve (R*(t)) of the process parameter (R(t));

c) determining a difference (D(t)) of the process parameter (R(t)) and its smoothed curve (R*(t)), D(t)=R(t)−R*(t); and

d) changing a process parameter of the flow-hole and thread-forming process based on the difference (D(t)),

wherein the process parameter (R(t)) is formed based on at least one of: the rotation speed (N), the torque (M), the feed force (F), and the penetration depth (Z).

2. The method of claim 1 wherein the smoothing used to determine the smoothed curve (R*(t)) is an exponential smoothing of first or higher order.

3. The method of claim 1 wherein changing the process parameter is initiated when the difference (D(t)) falls below or exceeds a preset threshold value(S).

4. The method of claim 3 wherein the threshold value(S) is formed based on a previously achieved maximum value (R* max ) of the smoothed parameter curve (R*(t) and a preset process value (α) according to the condition:

S=R* max /α.

5. The method of claim 1 wherein the process parameter R(t) is formed according to the condition:

R ( t )=( M·N )/( Z +β),

with (β) being a preset summand.

6. The method of claim 1 further comprising initiating a change to at least one of the rotation speed (N) and the feed force (F) based on the difference (D(t)) achieving a threshold value (S) such that D(t)≥(S).

7. The method of claim 1 further comprising:

a) applying a rotation speed (N) and a feed force (F) at a torque (M) to the fastener, in order to drive the fastener through a workpiece;

b) wherein the process parameter (R(t)) relates a power (P) driving the fastener to the penetration depth (Z) by which the fastener penetrates into the workpiece, where the power (P) is represented by the product of the rotation speed (N) and the torque (M), so that the process parameter (R(t)) satisfies the condition

R(t) is proportional to P(t)/Z, where P(t)=N(t)·M(t);

c) wherein the comparison of the difference (D(t)) of the process parameter (R(t)) and its smoothed curve (R*(t)) with the threshold value(S) is performed in order to determine in this way the time at which a frontmost segment of the fastener penetrates the workpiece;

d) reducing the rotation speed (N) responsive to the difference (D(t)) falling below or exceeding the threshold value(S); and

e) screwing the fastener into the workpiece while forming a thread in the workpiece.

8. The method of claim 7 wherein the fastener is a flow-hole screw.

9. A joining device comprising:

a controller configured to control one or more components for performing a flow-hole and thread-forming process in which a fastener comprising a flow-hole screw is driven through a workpiece with a speed (N), a torque (M), and a feed force (F) over a penetration depth (Z), the controller configured for:

issuing and receiving signals concerning the rotation speed (N), the torque (M), and the penetration depth (Z) of the flow-hole screw into the workpiece;

measuring a process parameter (R(t)) of the flow-hole and thread-forming process;

determining a smoothed curve (R*(t)) of the process parameter (R(t));

determining a difference (D(t)) of the process parameter (R(t)) and its smoothed curve (R*(t)), D(t)=R(t)−R*(t); and

based on the difference (D(t)), altering at least one of: the rotation speed (N), the feed force (F), and the torque (M),

wherein the process parameter (R(t)) is formed based on at least one of: the rotation speed (N), the torque (M), the feed force (F), and the penetration depth (Z).

10. The joining device of claim 9 wherein the smoothing used to determine the smoothed curve (R*(t)) is an exponential smoothing of first or higher order.

11. The joining device of claim 9 wherein changing the process parameter is initiated when the difference (D(t)) falls below or exceeds a preset threshold value (S).

12. The joining device of claim 11 wherein the threshold value(S) is formed based on a previously achieved maximum value (R* max ) of the smoothed parameter curve (R*(t)) and a preset process value (α).

13. The joining device of claim 9 wherein the process parameter (R(t)) is formed according to the condition:

R ( t )=( M·N )/( Z +β),

with (β) being a preset summand.

14. The joining device of claim 9 wherein the controller is further configured for initiating a change to at least one of the rotation speed (N) and the feed force (F) based on the difference (D(t)) achieving a threshold value(S) such that D(t)≥(S).

15. The joining device of claim 9 , wherein:

the controller is further configured for commanding application of a rotation speed (N) and a feed force (F) at a torque (M) to the fastener, in order to drive the fastener through a workpiece;

the process parameter (R(t)) relates a power (P) driving the fastener to the penetration depth (Z) by which the fastener penetrates into the workpiece, where the power (P) is represented by the product of the rotation speed (N) and the torque (M), so that the process parameter (R(t)) satisfies the condition

R(t) is proportional to P(t)/Z, where P(t)=N(t)·M(t);

the comparison of the difference (D(t)) of the process parameter (R(t)) and its smoothed curve (R*(t)) with the threshold value(S) is performed in order to determine in this way the time at which a frontmost segment of the fastener penetrates the workpiece;

the controller is further configured for commanding reduction of the rotation speed (N) responsive to the difference (D(t)) falling below or exceeding the threshold value(S); and

the controller is further configured for causing the fastener to be screwed into the workpiece while a thread is formed in the workpiece.

16. The joining device of claim 12 wherein the threshold value(S) is formed according to the condition: S=R* max /α.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (16)