Practices for handling cut-to-length parts with Creo and Windchill

[N-Pyn]

Hi everyone, 

Almost every design and manufacturing company uses some parts that are created by cutting some stock material (pipe, hose, aluminium extrusion, etc.) to a defined length without any other machining or other processing. Of course there is no need or sense in creating drawings for these kind of parts because the drawing would only tell what material to use and what length to cut it to.

At the moment our method for handling these is by first modeling the part in Creo with any way the engineer is used to and then creating a WTPart automatically during check-in.

Next the engineer goes to Windchill and adds a stock material WTPart to the structure of the new WTPart and sets the quantity of the BOM row to match with the length of the model. 

Here is an example of the resulting WTPart structure:

This is not a great method because if the length of the part is changed, it needs to be updated in multiple places: Model, part name and BOM row quantity. Also sometimes the engineer might forget to add the stock material item to the BOM.

What kind of workflows and practices do you have for handling these kinds of parts from Creo to Windchill and to ERP?

[Van_AG]

Look at the bulk item components

https://support.ptc.com/help/creo/creo_pma/r11.0/usascii/index.html#page/assembly/asm/About_Bulk_Items.html

I think this is the best practice in the case

[N-Pyn]

I have thought about this also and it seems to be the most promising option at the moment.

I was thinking that I could create templates for the parts created from stock material which would have a LENGTH parameter driving the model length. Then when engineers add a copy of that template to the assembly, they would have to also add the bulk item of the stock material. And then define the quantity of the bulk item with a Parameter Sum of that LENGTH parameter of all those parts to get the total need of the stock material. Bulk item would be associated to the WTPart of the stock material and the part created from the stock material would not have any WTPart associated to it.

The cutting lengths of the materials would be described in the assembly BOM and the WTPart structure would only give the total material reservation of each used stock material.

The problem with this would be that it seems that it would only work with stock materials that are measured in meters. It seems that Creo->Windchill integration converts the usage quantity of the stock material to meters even though the default quantity unit of the associated WTPart is cm or mm. We would have to add some unit conversion logic to our integration platform because our ERP will give errors if we try to push quantities with wrong units through.

[Yashraj_R]

Or you could try something like-

add an assembly driven attribute asm_qunitity

looks something like-

by-

• Creating parameter for the 'Component' in the assembly which gets it's value from a rule defined (based on business usecase- I added a dimension) another example is https://www.ptc.com/en/support/article/CS455101
• Mapping this attribute to assembly structure in windchill https://www.ptc.com/en/support/article/cs26565
• Further mapping the attribute to wt structure(same article- https://www.ptc.com/en/support/article/cs26565)
• Edit structure views to not display default units instead this

Not sure how ERP will handle it though, that part needs to be checked

Also note- I created the attribute as "Real number with units" to have both mentioned in the same box

could be helpful

[N-Pyn]

Hmm, using component parameters could possibly work. I could define the stock material and the length as component parameters in the assembly level and then use some magic in the PLM-ERP integration platform to create the BOM row with that stock material and length in ERP under that component item.

I just had some talks with our production planners and procurement and they want to have the items in our ERP in the format that I have in the screenshot of the starting post. But CAD designers want to have just the cut part as a .prt in the CAD model, so bulk items are out of the question because they would require us to create the cut parts as assemblies. So using component parameters could maybe be used to have the cut parts as just .prts in the CAD and Windchill, but then use the integration platform to insert the stock material and quantity afterwards.

But I think our integration developers will not like this idea because it would introduce more complexity to the integration logic. And also it might be a bit complicated process to create those component parameters for every cut-to-length part in an assembly. At least I cannot quickly think of any way to utilize templates or automation for that task.

I'll have to test this idea a bit and see if I can find an user friendly way to do it in CAD.

[BenLoosli]

Where I have worked in the past, every part going into an assembly had to have a part number. That also meant that the engineers had o design every part, even a simple tube at x.xx length. Some of those parts that were only length differences, we put into a family table that everyone could add to, but were told not to change any existing values. If you can live with bulk items, that is another way, but that does not allow the same 'part' to be used at different lengths in different assemblies. I prefer bulk items for things that are hard to quantify how much was used in any given assembly, like paint or grease.

[KenFarley]

I've done a good bit of stuff with 80/20 and Rexroth aluminum extrusions and this is exactly how we handled things, too. For a particular project and specific extrusion profile, I would start with a basic part and then add all the instances based on length, possible added features to handle different joining techniques, etc. If you set up the model parameters you can have things like the part description include a length specification, etc.

The only wrinkle I have seen is I guess Windchill does not play well with family table stuff. We don't have Windchill but this is something I've heard before.

[BenLoosli]

Windchill has no problems with family tables as long as you keep them simple and remember that you cannot delete any instances once created. At my last job, I had over 13,000 parts in my family tables all in Windchill. Some tables had over 1000 instances in them. I limited them to common hardware items, bolts, screws, washers, nuts, etc. that were very easy to build into a family table. Things like a bolt head, which is defined by the bolt nominal size, were put into relations, not the family table. The family table would be items that changed, bolt size, length, thread pitch, thread class and finish.

[N-Pyn]

I am very hesitant about instructing our users to start using family tables. I don't trust that they would not make some mistakes and cause problems that are really difficult and slow to fix. I have had to fix some family table errors in Windchill previously and it is not fun.

It's a can of worms I don't want to open. It's just easier to say to the engineers to never use family tables than let them use them in some cases and hope that the usage stays inside those limits.

[Dale_Rosema]

P/N: ####-####

We currently have a base number that defines the part, the first for digits of the number, a dash, then four digits that define the length.

e.g.

5020-2756 = a 2.25" diameter tube with (2) predefined holes at an overall length of 27.56".

They are all in a family table.

[N-Pyn]

That solution has two aspects that I do not like at all:
Part numbers encoded with information that can change and family tables.

[KenFarley]

The only time I will encode information in a part number is if it is necessary to specify a part which must be purchased. For example, SMC electronic components are always specified by part numbers that are a long string of letters and numbers that identify the base part, plus the numerous options available for it. You need the number to be encoded to properly specify the part.

Similarly, Carr Lane drill bushings and other tooling hardware are defined by a base part number plus a number that specifies the inner diameter of the component. You have to have that last number encoded in the part number in order to fully specify the thing.

But, those are special cases. Hardware related. I don't like encoded part numbers for things I'm creating. No matter what kind of scheme you think up, something always breaks it. Plus, if you realize you need to make something shorter or longer, instead of a simple revision change to the part, you need to "replace" it with a new part with a new number that reflects the new length.

[Catalina]

Hi @N-Pyn,

I wanted to see if you got the help you needed.

If so, please mark the appropriate reply as the Accepted Solution or please feel free to detail in a reply what has helped you and mark it as the Accepted Solution. It will help other members who may have the same question.

Of course, if you have more to share on your issue, please pursue the conversation.

Thanks,

[Srinivasan-Iyer]

Use AFX for such Stock items. Comes with tubes, Extruded Sections, Angles, Channels etc.

Will give you the cut length and the Total Length used of each section.

Bulk Item is typically used for Paint, Oil etc which are not modelled but need to exist in a BOM.

[N-Pyn]

How do you handle them in Windchill? Doesn't AFX create then a new item for each piece of a pipe or extruded profile?

And if I remember correctly, AFX doesn't even use the autogenerated number coming from Windchill. How do you handle numbering of those pieces?

[BenLoosli]

AFX dos create individual parts for everything you create. If your designers are just tossing together an assembly, unless they use the Reuse option, you end up with multiple parts with the same length.

AFX uses its own autogenerated numbering system with a base 'project' number and then an incremental numbering for the individual pieces.

Windchill has no problems with AFX generated numbers.

At my last company, we used AFX for structural racks. The designer would assign a base number and then add all of the parts, They did not use the Reuse button so we had many parts in the system with the same length. For the BOM, they would have to rename 1 component of each shape to our numbering system and then use a repeat region relation to change the quantity to AR for that base number.

[Srinivasan-Iyer]

AFX is used in the context of Assembly.

The Assembly number is Autogenerated (if the configuration is set to Auto-Number in Windchill)

The Assembly number is Prefixed to the Structural Member.

Length of the member comes from the actual length in the assembly.

One can Pattern or Reuse the same member (Section and Length would be identical)

See pic below

[N-Pyn]

What then ends up in the Windchill? A bunch of new unique items every time you create a new assembly with the AFX?

And what kind of manufacturing information is forwarded to the ERP? How are the relevant stock materials associated in the ERP to those new cut-to-length parts?

[Srinivasan-Iyer]

The picture below shows how it looks in Windchill. Please note that the part numbers are Prefixed with the Assembly Number. If the same member is used in multiple locations, the same would appear multiple times with the same part number.

length of the members are read from the assembly Length and is available in the drawing as a table. One may export the table to csv for incorporating in the manufacturing BOM.

You may test the same with respect to your ERP system. 

[N-Pyn]

I started to tackle this problem again and realized that bulk items do not look like they are after all a full solution for multiple reasons.

1. Unit of the item usage on the BOM is always the SI default instead of the default unit of the item (PTC pls fix). So the users need to go and fix the unit and quantity on the item structure in any case if they use materials that are measured in millimeters instead of meters, or grams instead of kilograms.

2. Bulk item definition seems to be very buggy. I have managed to get a fatal error in Creo multiple times when adding a bulk item and trying to define the quantity.

3. The process still involves designers having to update the quantity in multiple places. First in the cad model for the geometry and then separately for the bulk item. This could be automated by using measurements and relations to define the bulk item quantity, but we have some items that can be modeled as straight extrusions or curve sweeps. And I could not find a way for users to be able to either use length measurement OR distance measurement for defining the bulk item quantity. I can add a LENGTH parameter with the type of "Length measurement" and DISTANCE parameter with the type of "Distance measurement" and then use a relation to choose which one is used to drive the BOM_REPORT_QUANTITY parameter, but if I set the User Input setting on for both of the parameters, I am required to measure them both.

4, ESI transaction message merges the BOM usages. So if I have three pipes with lengths 100mm, 150mm and 200mm and add three corresponding bulk items to the CAD structure, the item structure looks correct in Windchill with each of the as a separate row with proper quantities. But when the structure is sent to ERP, the XML message automatically combines them to one row with a quantity of the sum of all occurences. This might be okay in some cases, but usually I would like to handle the ERP BOM as a cut list.

[JM_10432119]

I haven't used windchill in a while. But my two cents are having a part name reflect a part length is a waste of time, name it after it's location or something.

I'm fairly sure that windchill can accept parameters. I don't know if that can be used in quantity the way your system is set up. If not it may be worth handling cut to length parts differently where the quantity is bulk and there's a length parameter.

I associate all pipes to length in notes/ parameters there's different ways to do it. Since you may have curves which complicate automatically accounting for the length there could be an ADDED_L parameter to add to the first straight length like so.