Solidworks Project: Learning the Ropes - Entry #13: Molds Design Introduction

 Advanced Techniques - Molds Design Introduction

This entry is a continuation of the basic theory conveyed in SolidWorks Project: Learning the Ropes - Entry #1, where a 3D model of a pressure plate was created. As stated in Entry #1, the theory being tested in this blog series is based upon the internal tutorial program embedded within Solidworks, which is rumored to be all that is needed to reach intermediate to advanced level understanding of the software, with additional sources only needed for specialized uses or integration with other programs such as Blender for 3D printing. This series will document the progress of a first year engineering student with no prior experience with computer aided engineering design to weigh the theory based on outcomes. 

The process demonstrated followed the tutorials presented through the software itself, with minimal external assistance from other instructional sources.

Entry 13# covers the basics of Molds Design and uses a telephone handset as an example item to build a mold. The mold is composed of two parts - a core and a cavity. The inner surface of the model is duplicated by the core, while the cavity molds the outer surface. The core is divided from the cavity by a parting surface.  These two components are combined together and a medium (plastic or metal) is injected to fill the open areas within. After the material has set, the part is ejected by separating the core from the cavity.

A pre-generated file is provided of the model telephone shell, as seen in Fig. 1. The next step is to clear RealView Graphics, and on the computer this tutorial is being performed on, this is not an option. Fig. 2 shows the next step, which is to show the sketch info of the Boss-Extrude1 layer. From here, bosses are added for mounting the finished component to the rest of the phone assembly as seen in Figs. 3&4. These steps are repeated to create more mounting bosses.

Once these steps are complete, it’s time to Check for Draft.  This basically identifies edges which may be problematic for the mold process or removal from the mold once the item has set. Using Draft Analysis tools takes care of this with some easy input from the user. Part of this process is seen in Fig. 5.

Before the mold can accurately replicate the desired item, the shrink factor must be taken into account, which varies between different products .A scale tool is used for this. 

These tutorials now require using an active manager along with the feature manager to select different planes and layers of the component while changing the parameters for things such as the scalar and parting lines tool. When a pane is actively awaiting input, the feature manager opens in the graphics workspace.

Parting lines are created, followed by creating parting surfaces and preparing for the tooling split. Each of these aspects require minimal steps, all of which setup the Applying the Tooling Split section.  This begins with applying dimensions to the model plane and centering it within. This is seen in Fig. 9.

At this point, there was a disconnect between what the tutorial expected to happen and what actually happened. In the Tooling Split pane, the Core, Cavity and Parting Surface sections were suppose to be populated with one surface each, while only the Parting Surface section actually had a surface populated within. Retracing steps to try to correct this issue based on presumed operator error did not lead to a correction of the issue. The difference between what was expected and what was actually displayed can be seen in Fig. 10.

Unfortunately, this has led to an inability to proceed as the tooling split cannot be rebuilt, offering an error message “Cannot knit sheets together.”   

In conclusion, this has been yet another tutorial which has not been able to be completed. Despite being able to retrace steps to try to identify the issue, it is suspected that this particular instance is a case of user error and would require restarting the tutorial. This leads to a bigger general complaint of the tutorial process, which is the lack of a navigation tutorial which includes explanation of how to truly undo previous processes for troubleshooting purposes. While there is a standard “undo” function, this often does not reverse what was previously done, so something as simple as an accidental click anywhere on the workspace that interrupts a process can send a user off track in an irrecoverable manner and require restarting the tutorial from the beginning. More of these conclusions will be written up in the final entry.

Fig. 1. The model from which a mold shall be generated

Fig. 2. Sketch info is displayed.

Fig. 3 gives a bit of clarification as to how it should look when the Mounting Boss area is correctly selected.

Fig. 4. Creating the mounting boss.

Fig. 5. What the Draft Analysis manager options look like.

Fig. 6. Part of the Draft Analysis process.

Fig. 7. A look at simultaneous access of multiple panes.

Fig. 8. Using Draft Analysis to define parting lines.

Fig. 9. Adding dimensions and centering the model in the Tooling plane.

Fig. 10.  The surfaces expected, as seen on the right, were not populated, as per the empty fields in the pane on the left, which reflects upon the graphic in the workspace.