Understanding FreeCAD Lesson 3.1 (a) Retrospective and optimisation of Piston Crank Shaft Assembly

In lesson 3 part 1 we learnt how to create a master sketch in FreeCAD using the sketcher and then use that to create the piston head in the part design with revolves and pockets. There has been some questions ask in the comments in the subject of why I used a datum plane and the draft clone rather that the shape binder. In this retrospective I go over the reasons why and further optimise the model removing unnecessary datum constrains and using a formula to reference one of the constraints from the master sketch

This is a 4 (5) part lesson of how to create a piston head, connecting rod and crank shaft assembly, modelling them in the partdesign wb, assembling and finally simulating and animating these in the A2 plus workbench. We will be going through the master sketch workflow in the part design workbench and then the assembly workflow in the a2plus wb.

In Lesson 3 part 2 we continue with modelling both the connecting rod and crank shaft.

Lesson 3.2 Model a Piston Crank Shaft Assembly Animation in Part Design A2Plus

#FreeCAD , #CAD , #basics , #3DPrinting
Journey with me and

Donate:

Patreon

Subscribe:

Browse my Redbubble Shop:

[funkysod]

That's very good! As some of us mentioned the two datum planes was a bit redundant. As a creator, to go back and adress this, is great! That shows a humble attitude and the will to learn and teach! Your content has good value. Even if I've been using freecad since way back I pick up valuable thoughts and methods to use. Thanks again!

[timinwsac]

Well I've been stumbling along the learning freecad process for a few years now and this the best explanation of origin and datum planes, and when to use them, that I've run across.

[martinxp]

Great over view of both methods thanks!

[brianprice]

Another useful video. I thought your use of datum planes was a little overkill but it did highlight the versatility of them. There is more than one correct way to develop a solution - some are more efficient than others. For me, you have a good balance between teaching and using. Thank you.

[billstoner]

Another great video. I believe you could further refine the piston body by combining Sketch002 with Sketch003 and use 1 pocket for both features. Both features are on the same plane and both are through all. Thanks sharing you exceptional knowledge with all of newbies.😊

[macdroid]

I agree the Datum works, but a sket h can be placed in exactly the same way. Thus avoiding extra clutter in the model tree.

[brucewilliams]

You are doing such an awesome job with this videos. This has been so helpful in getting my head around the work flow. I appreciate understanding the datum plane workflow and understanding where it can be dispensed with for economy in a drawing. :)

[dragonlord]

well I think I need to do this again. I managed to delete the datum planes and added the circle with the +5mm but then I was told my sketch was under so will revert back and follow this again from the beginning
one thing I wonder, if you are a little off the centre line with, say, the large circle (or any part I guess) can you move the centre to the circle or are you stuffed? Thanks