Is there an easy way to insert fasteners when you are finished with modeling?

[AB_10071442]

I have relatively recently started working at the office, and I have worked in a way that I modeled my components, put them together and when everything was finished, I added fasteners using the "activate" command within the assembly. However, now I get a lot of issues when I try to copy components or make changes. Mostly, the fasteners which I inserted in the assembly are the cause of problems, e. g. holes just disappearing and dowel pins or screws being underconstrained. Does somebody maybe know whether there is a way of adding fasteners at the end of modeling which is less prone to problems when one is trying to make changes or copy components later on in the process of modeling? Thanks in advance for any ideas!

[mashton-2]

I would open the assembly level you want to add the component/s to and assemble the component using the assemble function from the ribbon. Rather than copying components particularly fasteners it is better to pattern the holes in the relevant part model and always create holes using the Hole tool.

Ensure you assemble your first fastener (screw, nut or whatever) to the lead (1st) hole in the pattern this will make the reference pattern more robust. Learn how to use pattern tables they are really powerful.

Always constrain from good solid features i.e datum planes.

[tbraxton]

Since you describe activating components in assembly mode, the most likely cause of your issue is that you are creating references for the fasteners to the assembly or other components. This prevents a component or sub assembly from regenerating outside the context of the assembly where you placed the fasteners. You can use the global reference viewer to observe the nature of the dependencies. If this is the case then there are better ways to manage this.

Skeletons, reference patterns, automatic assembly using layouts, and other options are available. If you can describe an example of your design intent and workflow that may guide suggestions tailored to your environment.

[AB_10071442]

Hello tbraxton, thank you for taking the time to answer my question and mentioning possibilities to insert fasteners! An example of my workflow would be like this: I create the individual components. I know how I want to locate them in relation to each other, so I create an assembly and constrain them using the location of the surfaces to each other.

Then, I activate the first component and configure the hole in the way that the table book says it. Then I set references and drag the hole to a position where it has enough wall thickness. Then I use mirror or pattern features to place a sufficient amount of fasteners. Then I activate the other component and place the hole coaxial to the above hole and configure it as well. Lastly, I create mirror features as described above to get the necessary amount of holes, then add fasteners using the "assemble" command" and constrain it using the respective holes.

If you have the time to look into my answer and give ideas on improvements, I would really appreciate it, but otherwise I am also very happy about your above answer and I am going to look into the features which you mentioned!

[pausob]

Like already mentioned by other people, your workflow could be improved by use of patterns which would also enable you to assemble a single fastener (or group) to a patterned hole and then system will be able to assemble the other ones "by reference".

Table patterns were mentioned; for what you showed in the videos, I think sketched-point driven patterns would be quite viable:

1) make a sketch with datum points to indicate hole centres locations.  You can use the mirror function to capture a symmetric design intent.  Note that this sketch can exist in the parent assembly, or in the part(s) (see below)

2) use the (1st) sketched point as the placement reference for the 1st hole.  Easiest is to start the hole tool with this sketch selected.

3) After the hole is created, pattern the rest of the holes using the "point pattern" option

Another aspect of "design intent" is also nicely captured in your videos: you need the holes in the yellow part to coincide with the ones in the green part.  So what you did is fine, but you have created dependencies - the axis of the threaded hole in the yellow part is to be "coincident" to the counterbored hole in the green part.  Moreover, this all depends on how the yellow part is placed relative to the green part - which is specified in the assembly.  So if you make any changes to the yellow part without having the assembly and the green part "in memory", the regeneration of the threaded holes will fail.  Creo is pretty unforgiving about these things.  The tools to examine the dependencies are available but they are cryptic and the process of "removing the dependencies" is manual. 

Again, that's all fine if that is your design intent - and maybe you don't need to change much except when making your copies, make sure you are copying the entire assembly.  Use save-as-copy on the assembly and you will have the option to make copies of the sub-components, and the dependencies will be "transferred" to the new copies.

The other methods mentioned (i.e., skeleton models and layouts) are from the advanced assembly extension, which is not part of the standard package.  In any case, there will be a similar dependency / design intent implications which should be considered.  In the example pictured in your videos, the skeleton or layout model would contain the hole pattern, and the green and yellow parts would reference this pattern.

I think the only other thing to mention is that there is the Intelligent Fasteners extension available which might improve the workflow related to fasteners.  I'd be curious to hear what others make of this extension; it seems pretty good but in my company it has not been adopted.  In my opinion, PTC brought out this extension way too late; companies that do CAD with pro/engineer / Creo have already developed their own fastener libraries and now it is just annoying that one is forced to pay for this extension and spend the money and  time to convert their library to work with it.  Especially when looking at how holes and fasteners are integrated into other CAD packages (for free).  Anyway, enough ranting, good luck!

[mashton-2]

Personally I don't like mirroring holes but the way I would do what you show in your videos is to do the first hole as you have done then pattern it using a table. Then save the table create the second hole using the same reference scheme i.e. equivalent faces/datums in the second part. Then import the pattern table into the pattern on the second part.

[tbraxton · Accepted solution]

I have created some models and implemented a solution using several of the techniques mentioned previously. Multibody, patterns, and external copy geometry features are used in this example to illustrate some of the possibilities. This is not the only way or the best way necessarily.

I used this approach since in your example you are working in assembly mode currently. This is a method to preserve that approach without creating assembly features and references. In general, assembly features should be avoided. It is intended to demonstrate what is possible with some of the top down design tools that are useful for what you want to do.

I created a master model for the blocks using multi body functionality and then created derivative parts for the yellow and green blocks from the master. These are then assembled in an assembly and the fasteners are added using reference patterns 

Refer to the video and the models (Creo 7) for more detail.