There is often a confusion between drawing no. and Item no. This article talks about the differences between the two and also the best practices to be adopted while creating Item numbers.
In OurSys ERP, the “Item Master” is for unique stock items. Items are to be defined from the inventory perspective. Therefore, by definition, all stock items like raw materials, finished goods, bought out components, packing materials, consumables, tools, fixtures, instruments, gauges etc. are all items.
In discrete manufacturing, every manufactured item has a drawing and thus a corresponding drawing number. There is a general practice to keep Drawing No. and Item No same. There is no harm in this until the drawing is revised. If the drawing is revised and you have some inventory of the previous revision in stock, how do you distinguish between the two? Therefore the best practice is to assign a distinct Item No to every revision. This way there is no confusion over the revision of the item in stock. This also helps in delivering the right spare part to the customer after any number of years. You do not need to save the drawing revision now in the order.
If you are using a 3D design software, every file/object that you create is equivalent to Drawing No. and not Item No. Therefore while importing BOM from 3D software, one has to either define file/object same as Item No. and then import or treat it as Drawing No. and then pull the associated Item No. in the BOM. In case there are more than one Item numbers associated with the drawing, the first Item No. in the list will get associated. We do not have the last mentioned functionality but we can provide it if required.
Sometimes the Drawing numbers are given by the customer and they release the next order with the same Item No. but a different Revision No. How do you handle this? Even in this case it is better to keep revision wise Item No. and use Customer Item No. field to store the Item No. that customer wants on the invoice. This way we can still continue to hold previous revision inventory under the earlier Item No. Keep Item No. same as Drawing No. only if the customer buys all the previous revision inventory and there is absolutely no chance of producing the item with previous drawing revision.
Sometimes, the drawing is a schematic drawing wherein the actual dimensions are written in the form of a table in the drawing. Here too, one must create a separate Item No for every distinct size and yet have the same Drawing No. associated with it in OurSys.
What to do if the drawing is the same but the MOC/grade is different. Again the same rule. Create distinct Item No. for every MOC/grade.
Sometimes, a single drawing is made for items of the same design but different colours. Well if you want OurSys to give you colour wise stock, it is better to create separate Item numbers and if colour does not matter then you may have the same Item No.
That brings us to a general rule that if the variation matters, have a distinct Item No