Surfacing And Blending: A Comprehensive Guide

Creating and Manipulating Surfaces with Surface and Curve Tools

A model's surfaces and curves may be constructed and altered using surface and curve tools, which also allow you to change curve tangents on the fly. In the surfacing section, students learned about the processes of creating, changing, and manipulating surfaces. There is also instruction on how to use surfacing tools to edit the curves and surfaces of parametric and nonparametric models that have been imported, and it teaches students how to change the form and shape of curves and patterns as well as faces and solids by modifying the geometry and rotating it as well as stretching it, tapering it, bending it, and twisting it. The border blend tool was used to create a boundary blended feature between reference entities that described the surface in one or two dimensions, and this feature was then blended between the reference entities.

The surface boundary was formed by selecting the first and last entities in each direction and placing them first and last in each direction.

In order to completely characterize the surface shape, additional reference items such as control points and boundary conditions could be introduced. The following criteria were used to select reference entities:

• In this study, reference entities included curves and part edges, as well as datum points and the ends of curves and edges.
• Reference entities were chosen in a sequential order for each direction in each direction. Reference entities, on the other hand, can be rearranged.

In the boundary blend tab, you'll find commands, tabs, and shortcut menus to get you started. Specifically, the following methods were followed:

Commands

The first direction collector that displayed the curve or edge chain references in the first direction was called the first direction collector. In the second way, the collector presented curve or edge chain references that were collected in the first direction.

The Curves

Chain dialog box is displayed, allowing for the modification of chain characteristics. When the blend check box was selected, the last curve was blended back into the first curve, resulting in a closed loop surface. Single-direction curves with no other collector are only relevant when the other collector is empty.

Constraints

To clarify, the boundary list was in charge of ensuring that chains were available for use in the boundary mix, as indicated previously. The boundary conditions, which were created to deal with tangency situations, were in responsibility of ensuring that the borders were aligned properly. In comparison to previous versions, this version contains a check box for inner edge tangency, which allows you to decide whether the inner edge of a blended surface is tangent in one or both directions at the time it is generated. A composite surface can be successfully smoothed without failure when four boundaries are defined and tangency (G1) or curvature (G2) connections are applied. This was also true when optimizing the surface form to smoothen a single surface (as opposed to a composite surface), and it was true when optimizing the surface form to smoothen both a single surface and a composite surface.

Control Points

When employing the general blending strategy, it is feasible to construct from the natural blend a surface approximation that is as close to the best as possible, and then to repeat the procedure for each input curve in order to produce the best surface approximation that is possible to obtain. Because the points were being added one at a time, the use of point to point functions to mix the points sequentially as they were being added was necessitated by the fact that they were being added one at a time. We were able to shape the surface by mapping the locations of control points on our input curves to the shape of the surface, which was something we had previously accomplished using control points. Because of the control points that were used to produce the surface contour, it has taken on a molded appearance.

Editing Surfaces and Curves of Imported Models with Surfacing Tools

Influencing curves collector

Curve chains are supplied to influence the shape of the blended surface or to forecast the direction of the blended surface. Where a result of this evaluation, the chains were edited as needed.

Smoothness Factor

In order to create a greater surface quality, this command was utilized to define the surface roughness, irregularities, and projections.

Patches in direction (First and Second)

Using this procedure, the number of patches in the u- and v- directions may be regulated at the end of the procedure. The patches were then stitched together to form the finished surface.

• Converting the surface to form a solid was challenging.
• The use of surfacing tool posed a great challenge as one had to learn the basics and implement it on the task given.
• Editing of reference curves and blending them while using constraints to form a boundary was difficult, one had to sketch almost perfect curves for them to produce the desired profile.
• The task involved the sketching of many surfaces and this was time consuming.

• In the context of surface assistance, the use of a Creo parametric reference book for surface aid is discussed in detail. Engineers have been able to produce difficult-to-machine geometries with high levels of engineering precision and accuracy as a result of the advancement in their understanding of the surface tool and Creo as a whole.
• The use of tutorials from internet sources to enable altering of already constructed surface geometry before translating it into a solid.

 

Figure 1: Selecting planes

 

Figure 2: Sketching of drill housing profile 

 

Figure 3: Dimensioning of the profile 

 

Figure 4: Sketching of screw holes for assembly

1. Creating a manufacturing file

Immediately following the development of the needed part, it is important to produce a mold cavity for the item that will be assembled. The piece will be utilized to form a cavity for the mold that will be used later on in the production process. A new Creo file is created after the mold cavity has been selected and the production option has been unfolded. To be used in the manufacturing window, the reference model has been selected for inclusion. At this point, the part file is imported into the system. You'll need to employ a coordinate system in order to determine the origin of the mold cavity. This is accomplished through the datum portion of the top toolbar, and a new

coordinate system is generated in the center of the screen. The original coordinate system is utilized as a point of reference, and the dimensions are changed to account for this.

 

Figure 5: Inserting part 

 

Figure 6: Creating workpiece

When a workpiece is selected from the taskbar, this command brings up a menu for you to choose from. The default model is the component that was originally drawn, and the command closes the context menu. The origin of the mold is then identified by selecting a new coordinate system from the left-hand menu or a point on the model from the right-hand menu on the computer screen. It is possible to view the orientation of the mold before it is created. Offsets can be utilized to adjust the size of a mold to meet your specific needs and specifications. This step is necessary in order to ensure that the part will fit inside the template.

 

Figure 7: Inserting the part and definition of mold parameters

 

Figure 8: Workpiece

The mold's perspective has been modified to show a darkish region with hidden lines, which makes it easier to notice both the component and the mold in the final product. The tool path is then constructed with the use of the sketch tool, which defines the path that the tool will take in order to form the cavity in the mold. It is necessary that the path connects the mold's exterior with the thing located inside the mold. The sketching plane is determined by the plane on which the runner extends out to contact the mold surface. Choose "Runner" from the production features drop-down menu on the right, and the pop-up menu on the right will guide you through the process. The shape and proportions of the runner have been decided. The "pick path" option in the menu is used to select the flow path, and the previous drawing is used as a starting point. It is necessary to select the entire mold by selecting it in the Intersected Components panel. should display on the screen. It is only when the process is completed that the runner is seen.

This is accomplished through the use of the commands "parting surface" and "sketch". When creating the parting line on the mold, a plane is selected on which the line will be drawn. The line must pass through both ends, depending on the plane that is selected. Following that, the line is extruded to the next surface on the opposite side of the surface.

 

Figure 9: Defining parting surface and runner

Under the "mold volume" command, the option "split volume" has been selected. In this way, the mold can be separated into two separate volumes. The split surface is made up of the parting surface and the dividing surface. The pieces can be separated into two independent files in order to make editing more convenient. 

 

Figure 10: Defining the refpart cutout 

 

Figure 11:  Creating two parting surfaces

 

Figure 12: Upper mold

 

Figure 13: Lower mold

• Selection of the best parting surface
• Creating the tool path
• Creating runners
• The task involved the use of many commands that depended on each other, thus an error in one command resulted in malfunctioning of the consecutive commands.
• Defining the split volume

Solutions to the problems encountered

• Practicing of mold design by using simple geometries that are easy to produce. This sharpened the skills gained and helped in saving time when tackling the task.
• The use of tutorials from internet sources to enable one follow the proper guide to avoid redoing the task severally before getting it right

The manufacturing template is used to create the workpiece. This is followed by setting the dimensions of the blank. It is selected automatically from the assembly of mold. The operation is selected, milling and the tool parameters are set accordingly. The tool paths are generated and the path is simulated. The code is then generated.

 

Figure 14: Creating manufacturing

 

Figure 15: Setting workpiece size 

 

Figure 16: Selecting operation

 

Figure 17: Tools path 

 

Figure 18: Tool path for face milling

 

Figure 19: Tool path simulation 

 

Figure 20: Part of CNC code 

Using the simulation tool included in PTC Creo, engineers and designers may visualize and understand how the computer numerical control machining process would take place in the real world when a workpiece is fed into a milling machine. The following are some of the other advantages:

• Machining operations and tools can be programmed and adjusted for maximum efficiency and the lowest possible error rate.
• Design and engineering problems can be found, and software improvements can be made.

Conclusion

The task of component modeling, mold splitting, and mold machining of the drill cover has been completed fully in this report. The following challenges were faced:

• Inability to create a good geometry that would allow for creation of split volume was a great challenge but the modification permitted one to do so after several attempts.
• The use of inaccurate or derived dimensions, this posed a great challenge when developing the parts, workpiece and the mould.
• The part, mould and the manufacturing of drill housing was done successfully. 

References

Bryce, D. M. (1998). Plastic injection molding: Mold design and construction fundamentals. Society of Manufacturing Engineers.

TOOGOOD, R. O. G. E. R. (2019). Creo Parametric 6.0 advanced tutorial. SDC PUBNS.

Dotchev, K., & Popov, I. (2021). Cad/Cam with Creo parametric step-by-step tutorial for versions 4.0, 5.0, and 6.0. World Scientific.

KANIFE, P. A. U. L. O. B. I. O. R. A. (2018). Computer Aided Virtual Manufacturing using Creo Parametric: Easy to learn step by Step Guide. SPRINGER.