By Jennifer MacMillan
Thanks so much to all of you that joined me for my latest Webcast on Joint Connections. As I mentioned, this material was all taught directly from the content that is available in Chapter 17 of the Autodesk Inventor 2014 Introduction to Solid Modeling training guide. From the feedback that I received after the session many of you are excited about this new tool in 2014 and see it as a great step for Autodesk Inventor. Hope you enjoy it!
I thought that I would summarize some of the Tips that I mentioned and repeat some of the questions that were asked. I also posted the link to the recorded session at the bottom of this blog.
- The Mini-toolbar is great for defining the Joint type and its placement references however you will need to use the Place Joint dialog box to assign Limits to any of the Joints using the Limits tab. The dialog box is also required if you want to replay the preview animation that displays on Joint placement.
- All assigned Joints are listed in the Model Browser within the Component as well as in the Relationship node at the top of the Model Browser.
- Assign names to your Joints to describe their use in the model. This is especially helpful when looking at the Joints in the Relationship node of the Model Browser. Without names you will have little idea of where they are used in the model. A descriptive name helps. You can rename in the Model Browser or in the Joint dialog box (not the mini-toolbar)
- The Automatic Joint type allows the system to assume the type that you require based on the Connection points that are selected as references. If the assumption is not correct you can select the appropriate type from the drop-down list.
- The Align area is optional. It may or may not be required to orient components when the Connection points are selected. It enables you to further refine the orientation of the two connected components if the assumed orientation is not correct.
- Limits on a Joint connection can be assigned for linear or angular motion.
- Use Constraints in conjunction with Joints to lock down any degrees of freedom that remains after a Joint is added.
- When assembling components using Joints, a component within the models must be grounded to appropriately test the dynamic function of the components. Consider temporarily grounding components to ease testing.
Q1. How do you define the references for motion limits?
A1. The motion limits can only be defined using the Place Joint dialog box (not the mini-toolbar). In the dialog box, select the Limits tab. On this tab you have the ability to set limits using linear or angular values. Enter start and end values to define the allowable range. This range is measured from the connection point reference that was selected to connect the components. Limits can be added after the Joint has been created by Editing the Joint.
Q2. Are joints the future for Inventor and should we be using them rather than constraints? I understand that joints translate better for simulation environments.
A2. I wish that I could tell you the answer to this! Unfortunately this type of information is something that Autodesk doesn’t share. Over the last few releases Autodesk has being focusing on ease of use. This enhancement falls in line with this strategy. It is a great way to assemble components with intuitive easily understood industry standard connections.
Q3. Can joints be converted to constraints at a later date? Or must they be deleted and constraints applied?
A3. Unfortunately existing constraints must be deleted and recreated as Joints.
Q4. Is there a Joint Connection Type that allows me to move in 2 translational directions on a plane?
A4. The Planar Joint type enables two translational and one rotational DOF on a plane. Once you define the connection to the required plane you will have to add an additional Constraint using the Constraint tool to lock down rotation if you don’t need this DOF
Hope that this Webcast and notes helped you learn how to incorporate joints in your assembly models.
To view my full webcast recording visit: http://youtu.be/jaTVJQkNKSI