Apics and ax master planning (1)-Phantom Bill of Material virtual item

[Preface]
As an ERP software, MPs and MRP should be the core part. Although ax master planning introduces various parameters of the ax master plan, from the business perspective, how do we understand those parameters? How should we set these parameters to be correct? It has been bothering me and I always hope to see some Article I have never seen how to use ax's master planning, but I have been reading some books about apics these days. I wanted to write the Reading Notes all the way, but "I have to get a glimpse of it on paper, I know that this matter needs to be done ", so we should combine the use of ax's master planning to see if Ax is in line with these classic MRPII theories. At the beginning, I wanted to read all the books and study the master planning parameters of ax before writing them again. However, I felt a little confused about the smell of corn. I forgot it after I tested it, so let's take a look at it one by one. On the one hand, I am not familiar with the knowledge system of apics, and on the other hand, I am not familiar with the master planning of ax. Therefore, it is inevitable that I will miss a thousand points in writing, hoping to get some advice from experts.
Bibliography:
Apics dictionary 12th
MRPII Standard System
Introduction to Materials Management
This article first talks about the phontom Bom, because this concept has been used in this project recently, which is implemented in ax. But read apics books, it is found that some concepts are not the same as those in ax. So write this article to record it.

First, extract the definition of virtual items in apics Dictionary (see apics dictionary 98 ):
Phantom Bill of Material: A Bill of Material coding and structuring technique used primarily for transient (non-stocked) subassemblies. for the transient item, lead time is set to zero and the order quantity to Lot-for-lot. this permits MRP logic to drive requirements straight through the phantom item to its components, but the MRP system usually retains its ability to net against any occasional inventories of the item. this technique also facilitates the use of common bills of material for engineering and manufacturing.
From the definition of the apics dictionary, we can see that virtual items are mainly used to deal with transient parts, which are generally not in stock, and the MRP operation logic directly breaks down the requirements of this material into its components. But in general, the MRP system will consider the occasional inventory of this component when making the net demand. In Chapter 6th of MRPII standard system, virtual items are also introduced, page 70th.
In this chapter, it emphasizes that virtual items need to deal with occasional inventory situations. That is to say, if virtual items exist in inventory, virtual items need to be consumed first, after consumption, expand the requirement to the virtual item component, and give an example to illustrate the advantages of such a function. In general, a material a is composed of B and C, if the process changes one day, B needs to replace it with D, but it must be replaced after B is used up. In this case, B can be set as a virtual item, and then D is used as a component of B, in this way, after B is used up without inventory, the demand will be directly expanded to its component D according to the logic of the virtual item, thus acting as a substitute for the material. It mentioned that it is wrong to directly expand the demand to the virtual item component without considering the inventory of virtual items.
In fact, from the above two classic tutorials, the attitudes towards virtual items are different. The apics dictionary only means that the MRP system usually considers the inventory of virtual items when calculating the net demand, this feature is not particularly emphasized, but the MRPII standard system emphasizes that virtual item inventory must be considered; otherwise, it is incorrect.

The following describes the implementation logic of ax:
From the above description, if a material is a phantom-type material, it must be a BOM to include components. First, create a phantom material B. The material type must be Bom. In fact, the phantom attribute of a material is an attribute when it is used as the BOM of its parent material, the material itself is no different from other materials. For example, the B material we created may be of the phantom type in the BOM line as the parent material, however, the BOM line of other materials may not be phantom. Of course, we only discuss this possibility. Generally, a company uses a material as an instantaneous part for processing.
Here, how do I implement the phantom material mentioned in apics theory step by step in ax? We create three materials A, B, and C, where A is composed of one B and B is composed of one C, A and B are BOM materials, and C are BOM materials. Of course, B is the Phantom we are going to demonstrate. Material B is essentially the same as material a in terms of attributes, only B is used as the phantom type in the BOM of.
Creating a bill of materials is a basic operation. View only one parameter of item B (inventory management-> item-> reference-> virtual)

This parameter is actually a default value. If this option is selected when the item is used as the item list for other items, the type of the item list line is virtual, of course, it can be changed to another row type.
The row type can be seen on the General tab of the item list row of A, as shown in:

In this way, the basic information is created. to verify its logic, we create a sales order of material a with a quantity of 100, so that it can generate requirements and run master planning, the planned orders generated are as follows:

Apparently, the planned purchase order for its sub-Material C is directly generated instead of the planned production order for B, that is, the requirement is directly transferred to the sub-Material C of B, this is in line with the definition of apics. What will happen if B has inventory? According to the definition of apics dictionary, B's inventory should be used first, and B's inventory cannot meet the requirements before being expanded into sub-Material C.
We perform inventory check to cover 100 B Inventory profit items:

And then run the master planning, then the theoretical line should not generate the C plan procurement order, because the existing inventory can meet the demand. Run master planning again. The result is as follows:

From this we can see that it still produces C's planned procurement order, so ax did not consider B's current quantity, but directly generated C's planned procurement order.
So it seems that the processing of ax's virtual items is still different from the definition in apics.
However, it is harmless to see how it is used.