Wednesday, May 29, 2013

Create depended assembly parts using blocks

 

Create depended assembly parts using blocks

 

Did you ever match a bunch of holes and shapes at one part with others while making an assembly?
 
 
 
Pic.1
And let add some real design-in-progress stuff – those holes may eventually changed at the base part and it will require the changes at all depended parts. How boring and time consuming to change everything and oops.... some other depended parts will show not appropriate change. When you see it you probably already spent a while to change almost all previous depended parts… The fresh idea of changing some design of the base part may perish just from one thought of changing a dozen parts to fit the change done on basic part. Along with this manual changes the errors could be easily done.

So here is idea of tie-up depended parts by their parameters come up.

There are several ways to make parts depended from each other, by Excel file, by linking the parameters from other part or by creating the single IPT file with all necessary parameters called as Drive Sketch.

Each mentioned way has one time consuming thing in common. Literally we must create depended stuff from scratch at every new part using linked parameters taken either from the same Excel or the same drive sketch or other part. This is quite time consuming way and if depended holes or special designs are complicated it takes a long and boring while. This process is also vulnerable for errors.

The other way is create depended parts using a Derive but this function will force us to create a part in the same coordinates, other words in absolutely not flexible way.

The one more problem is the assembly does not have all depended holes same in design. For example you should match a round bolt hole in one part with round-extended hole in other part and some other design for a third part as you can see on picture 1. Depended parts could be absolutely different in overall shape as they are in real assembly but have dependency in the holes pattern and shape. As you can see at example at picture 1 the parts #1,#2 and #3 are fit each other but have different holes shape and different in overall shape.

Making depended parts

Chapter 1. The proposed way is a mix of Drive Sketch and Deriving technique with using Blocks and it is quite simple. From the beginning let’s talk about an assembly designing from scratch.

Initially let create a new ipt file with a single sketch with all necessary holes and shapes which fit each other as they must correspond and fit each other between depended parts. It will be the one Drive Sketch for all depended files. As seen from pic. 2 the round extended holes are correspond to square shaped holes and other bigger round extended holes are fit for round holes for bolts.

Create a block based on the holes and shape pattern. This pattern may include the fold-in simple blocks as you can see on picture. For instance the round extended holes are blocks. In this way it will be much easier to spread them all over the pattern and make no errors. Assign a name for this Block to make it easy to find it later.


Pic 2

Create or take existing part you need to be depended and make a Derive of the Drive Sketch file you just created. Choose the only block(s) you just created, see pic 3. Rule out Sketch and other stuff you do not need.


Pic 3

Now you are flexible and free in positioning of this block in this part. You can place it wherever you want not depending from planes and coordinates. Create a new sketch and place the block there. Once you make this block fully constrained it will change a color as fully constrained part. All process of inserting and constraining takes just few clicks compare to creating the similar pattern using linked parameters, see picture 4. This linked block is not accessible for editing. It could be changed only in original Drive Sketch. This block could be mirrored.

Pic 4

As seen from picture 4 the Sketch23 consisting the only one block derived from Drive Sketch file. Choose the required holes for this part and cut them. Use Ctr+Select if you accidentally choose a wrong hole.
 
 
 Pic 5
Choose and make required holes on all depended parts, see pictures 5 and 6.

 
Pic 6
 
As you can see from pictures 5 and 6 you can choose the required for certain part holes and be sure they will always fit each other as they fit at the Drive Sketch block. Once changes will be done to the Drive Sketch block they will affect all depended parts at once. You can be always sure all depended parts are fit each other after every change done to single Drive Sketch block. You also can be sure all shapes will be changed properly at all depended parts.
 
Chapter 2. This way of making depended parts can tie up some group of parts depending from one base part(s) dictating the holes pattern or special shapes or many etc. You will be lucky if holes pattern will be evenly spread and could be easy duplicated by Pattern tool with exporting just several parameters.
Mostly in real assembly holes patterns are not evenly spread and making the same and depended pattern at other depended part yon can be finally lost in dozens of tie-up parameters and errors and spend a lot of time
 

 
ADVATAGES
·   Easy and vivid way to make depended parts without big efforts.
·   Any alterations in parameters and depended shapes are done at same and single Drive Sketch; it is not required to jump between rows of depended parts to make changes in each file.
·   Much less errors due to “forgetting” to make a change or wrong change in some depended part.
·   All holes and shapes are visible at same pattern; this will make less effort changing them correctly and all from one step. For example we started with M6 bolts and then decided to change them to M8. All holes and special shapes in depended parts must be changed to other size. So we see all depended holes at the same sketch and have much less chances to miss some changes because we clearly see all of them.
·   It resembles the nature way of creating a puncture stamp and does different parts with exactly the same pattern. Compare to tie-up parts by linked parameters we can create less errors when we will change the initial sketch.
·   We can add or deduct additional shapes and holes in our Drive Sketch and we will instantly have them available at all parts. Just imagine we decided to set one more fixture and we create some new holes and corresponded holes at Drive Sketch block and here is a miracle begins. All we need is to choose fresh holes at our parts and cut them. They are already at the right place! If we would do it by parameters we should update the linked file, then choose the new parameters, then create the new hole – at least several times longer and vulnerable to errors.
·   Easy way to keep some standards on common and special holes and shapes between all depended parts in assembly since we use the sole source and do not creating them from scratch at each file.
·   This way also exports the engaged parameters as long as Derive is used. By editing the derived parts you can also add some more required parameters from base part without need to make an additional link between base and depended parts.
 
Importand.
1. Make Rebuild All after each Drive Sketch block change at main assembly or depended parts. Inventor not always automatically follows all changes made to Drive Sketch block.
 
Regards,
Orest Yavtushenko, Chief Designer, Holography Ltd


This article is about easy and sure way of making the depended parts in the assembly while making a new assembly design. The goal of making depended parts is changes we will make to one basic part will affect all depended parts automatically without need to change depended parts manually one by one