Autoinitialization in a three-dimensional modeling machine

• US 6,629,011 B1
• Filed: 07/17/2000
• Issued: 09/30/2003
• Est. Priority Date: 07/17/2000
• Status: Active Grant

• Current Assignee: Stratasys Incorporated
• Original Assignee: Stratasys Incorporated
• Inventors: Batchelder, J. Samuel, Calderon, Joseph L., Pollard, David L.
• Primary Examiner(s): Picard, Leo
• Assistant Examiner(s): RODRIGUEZ, PAUL L
• Application Number:
  US09/618,169
• Time in Patent Office: 1,170 Days
• Field of Search: 700/57, 700/60-62, 700/64, 700/114, 700/117-119, 700/123, 700/124, 700/160, 700/163, 700/186, 700/190, 700/192-195, 700/302, 700/98, 702/33, 702/105, 702/168, 425/135, 425/375, 264/497, 264/308, 264/401
• US Class Current: 700/119
• CPC Class Codes: B29C 41/36 Feeding the material on to the mould, core or other substrate
• CPC Class Codes: B29C 41/52 Measuring, controlling or regulating
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/118 using filamentary material being melted, e.g. fused deposition modelling [FDM]
• CPC Class Codes: G05B 19/4097 characterised by using design data to control NC machines, e.g. CAD/CAM G05B19/4093 takes precedence
• CPC Class Codes: G05B 2219/49008 Making 3-D object with model in computer memory

Abstract

Disclosed are a method and apparatus for initializing an additive process computer-controlled three-dimensional modeling machine which builds models on a modeling platform. The method, without operator intervention, senses the top surface of a substrate or other object mounted on the platform at a variety of preselected x, y locations and records the z-axis positions of the platform corresponding to the sensing of the object. Using the recorded z-axis positions, a z-start position for the modeling platform is calculated. The platform can be automatically placed at the calculated z-start position. The recorded z-axis positions can further be used to define a plane fitted to the substrate top surface. Optionally, the model can be built in a coordinate system defined by the plane.

Claims

1. In a machine that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a substrate mounted on a platform movable along a z-axis, a method for initializing the machine, the method comprising tile steps of:

(a) sensing the top surface of a substrate mounted on the platform at multiple x,y locations by driving the substrate against an overhead plunger at each of the locations;

(b) electrically recording the z-axis positions of the platform corresponding to the sensing of the substrate; and

(c) using the plurality of recorded z-axis positions to calculate a z-start position of the platform.

2. The method of claim 1 and further comprising the step of:

automatically positioning the platform at the calculated z-start position.

3. The method of claim 1 and further comprising the steps of:

comparing the recorded z-axis positions to determine whether the top surface of the substrate is approximately parallel to an xy-plane; and

providing an operator notification if the top surface of the substrate is determined not to be approximately parallel to the xy-plane.

4. The method of claim 1 wherein step (c) includes performing calculations based on the recorded z-axis positions to define a coordinate system fitted to the substrate top surface.

5. The method of claim 4 and further comprising the step of building an object in the coordinate system of the substrate.

6. In a machine that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a substrate mounted on a platform movable along a z-axis, a method for initializing the machine, the method comprising the steps of:

(a) sensing the top surface of an object mounted on the platform at multiple x,y locations by driving the object against an overhead plunger at each of the locations;

(b) electrically recording the z-axis positions of the platform corresponding to the sensing of the object;

(c) comparing each recorded z-axis position to an expected range of z-axis positions; and

(d) providing an operator notification if any of the recorded z-axis positions are not within the expected range of z-axis positions.

7. The method of claim 6 and further comprising the step of using the plurality of recorded z-axis positions to calculate a z-start position of the platform, it the recorded z-axis positions are all within the expected range of z-axis positions.

8. In a machine that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a substrate mounted on a platform movable along a z-axis, a method for initializing the machine, the method comprising the steps of:

(a) positioning a plunging means above a pre-selected x, y location of a substrate mounted on the platform;

(b) raising the platform to drive a top surface of the substrate against the plunging means;

(c) electrically detecting contact by the substrate against the plunging means and responsively providing a detection indication;

(d) responsive to the detection indication of step (c), electrically recording the z-axis position of the platform corresponding to the detected contact between the substrate and the plunging means;

(e) repeating steps (a) through (d) at a plurality of other pre-selected x, y locations to obtain a plurality of recorded z-axis positions; and

(f) using the plurality of recorded z-axis positions to calculate a z-start position of the platform.

9. The method of claim 8 and further comprising the step of:

automatically positioning the platform at the calculated z-start position.

10. The method of claim 8 and further comprising the step of:

switching the plunging means to a stored position where it will not interfere with the building of an object, after completion of step (e).

11. The method of claim 8 and further comprising the steps of:

comparing the recorded z-axis positions to determine whether the top surface of the substrate is approximately parallel to an xy-plane; and

providing an operator notification if the top surface of the substrate is determined not to be approximately parallel to the xy-plane.

12. The method of claim 8 wherein step (f) includes performing calculations based on the recorded z-axis positions to define a coordinate system fitted to the substrate top surface.

13. The method of claim 12 and further comprising the step of:

building an object in the coordinate system of the substrate.

14. In a machine that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a substrate mounted on a platform movable along a z-axis, a method for initializing the machine, the method comprising the steps of:

(a) positioning a plunging means above a selected x, y location of the platform;

(b) raising the platform to drive an object carried by the platform against the plunging means;

(c) electrically detecting contact by the object against the plunging means and responsively providing a detection indication;

(d) responsive to the detection indication of step (c), electrically recording the z-axis position of the platform corresponding to the detected contact between the object and the plunging means;

(e) repeating steps (a) through (d) at a plurality of other selected x, y locations of the platform;

(f) comparing the recorded z-axis positions to an expected range of z-axis positions;

and

(g) providing an operator notification if any of the recorded z-axis positions are not within the expected range of z-axis positions.

15. In a machine that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a substrate mounted on a platform movable along a z-axis, a method for initializing the machine, the method comprising the steps of:

(a) positioning a plunging means above a selected x, y location of an object under construction;

(b) raising the platform to drive the object against the plunging means;

(c) electrically detecting contact by the object against the plunging means and responsively providing a detection indication;

(d) responsive to the detection indication of step (c), electrically recording the z-axis position of the platform corresponding to the detected contact between the object and the plunging means;

(e) repeating steps (a) through (d) at a plurality of other selected x, y locations of the object to obtain a plurality of recorded z-axis positions;

(f) comparing the recorded z-axis positions to a set of coordinates defining the object; and

(g) determining the coordinates at which to continue constructing the object based on the results of the comparison.

16. In a machine that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a substrate mounted on a platform movable along a z-axis machine, a method for initializing the machine, the method comprising, the steps of:

(a) positioning a plunging means in a downward position above a pre-selected x, y location of a substrate mounted on the platform;

(b) raising the platform to drive the plunging means upward under force of contact with a top surface of the substrate;

(c) electrically detecting movement of the plunging, means to a sensing location located a predetermined distance along the z-axis from the downward position;

(d) electrically recording the z-axis position of the platform corresponding to the instant in time at which the plunging means is detected at the sensing location;

(e) repeating steps (a) through (d) at a plurality of other pre-selected x, y locations of the substrate to obtain a plurality of recorded z-axis positions; and

(f) using the plurality of recorded z-axis positions to calculate a z-start position of the platform.

17. The method of claim 16 and further comprising the step of:

automatically positioning the platform at the calculated z-start position.

18. The method of claim 16 and further comprising the step of:

switching the plunging means to a stored position where it will not interfere with the building of an object, after completion of step (e).

19. The method of claim 16 and further comprising the steps of:

comparing the recorded z-axis positions to determine whether the top surface of the substrate is approximately parallel to an xy-plane; and

providing an operator notification if the top surface of the substrate is determined not to be approximately parallel to the xy-plane.

20. The method of claim 16 wherein step (f) includes performing calculations based on the recorded z-axis positions to define a coordinate system fitted to the substrate top surface.

21. In a machine that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a substrate mounted on a platform movable along a z-axis, a method for initializing the machine, the method comprising the steps of:

(a) positioning a plunging means in a downward position above a pre-selected x, y location of a substrate mounted on the platform;

(b) raising the platform to drive the plunging means upward under force of contact with the substrate;

(c) electrically detecting movement of the plunging means to a sensing location located a predetermined distance along the z-axis from the downward position;

(d) electrically recording the z-axis position of the platform corresponding to the instant in time at which the plunging means is detected at the sensing location;

(e) using the recorded z-axis position to calculate a z-start position of the platform; and

(f) automatically positioning the platform at the calculated z-start position.

22. In an apparatus for building up three-dimensional objects under the control of a controller by depositing modeling material from the a nozzle of an extrusion head that moves in an xy-plane onto a removable substrate located beneath the extrusion head in a modeling envelope and mounted on a platform that moves along a z-axis, the improvement comprising:

a plunging means mounted to the extrusion head, the plunging means being maintained at a stored position higher than the extrusion head nozzle during deposition of modeling material and switched to an actuated position beneath the extrusion head nozzle to execute an initialization routine;

a sensing means electrically connected to the controller for detecting contact by the substrate against the plunging means and responsively providing a detection indication to the controller; and

means for calculating a z-start position for the platform based upon a plurality of recorded z-axis positions of the platform, each recorded z-axis position corresponding to an instant in time at which the sensing means provides a detection indication in response to driving the platform along the z-axis towards the extrusion head while the extrusion head positions the plunging means in the activated position above a unique preselected x, y location of the substrate.

23. The apparatus of claim 22, wherein the plunging means in its actuated position is movable by application of an upward force to a sensing location a predetermined distance above the actuated position, and the sensing means detects contact by the substrate against the plunging means at the sensing location.

24. The apparatus of claim 22 and further comprising:

an actuator coupled to the plunging means for switching the plunger means between its stored and actuated positions.

25. The apparatus of claim 24, wherein the actuator comprises a bar which slides from side to side in response to application of horizontal force, the bar having a rightward position at which it extends past the extrusion head on a right side thereof and a leftward position at which it extends past the extrusion head on a left side thereof, and the bar being coupled to the plunging means by a pin which alternately slides up and down along a ramped groove in the horizontal bar when the bar is moved between its rightward and leftward positions.

26. A sensor assembly for use in finding a z-start position of a modeling platform in an apparatus that builds up three-dimensional objects under the control of a controller by depositing modeling material onto a removable substrate supported by the platform the sensor assembly comprising:

a plunger having a raised stored position and lowered actuated position, the plunger in its actuated position being movable by application of an upward force to a sensing location a predetermined distance above the actuated position;

a sensor for providing an electrical signal to the controller indicating whether the plunger is detected at the sensing location; and

an actuator coupled to the plunger for switching the plunger from its stored position to its actuated position for use in executing a z-axis initialization routine and switching the plunger back to its stored position upon completion of the routine, wherein the actuator comprises a bar which slides from side to side in response to application of horizontal force, the bar having a rightward position at which it extends past the plunger on a right side thereof and a leftward position at which it extends past the plunger on a left side thereof.

27. The apparatus of claim 26, wherein the bar is coupled to the plunger by a pin which alternately slides up and down along a ramped groove in the bar when the bar is moved between its rightward and leftward positions.