Manufactured Lead Time Calculation

I have scoured the posts and the MRP Tech Reference documentation to no avail. What I am trying to accomplish is to determine the lead time of a manufactured part given we have no components on hand. I need to take into account the longest lead time of the purchased components to calculate the “Lead Time” for the Manufactured item.

I have …

  1. Run the Manufacturing Lead time Calculation on Several parts. 1 particular part that contains 2 purchased parts with lead times of 21 and 28 days yields a Cumulative lead time of 116 days, This Level Time of 116 days and Top Level of 116 days. Another item run with both purchased parts and manufactured parts in the BOM returned 0 on all lead times. These were run with and without the Include Sub assemblies checked. All times except Rough Cut Parameters are checked in Site Maintenance( I did have the Rough Cut Parameters checked as part of the test cycle though).
    Standard production times are used in the Operations to capture labor and burden.

  2. Experimented with the Min/Max Mass update… I feel that I need more than 365 days of history to be accurate. My preference would be to keep as much of the processing within Epicor. We currently use an external spreadsheet (uggghhhh) to calculate Min Max Levels now. ( Where does Epicor get the lead time to make its calculations ??)

Am I misunderstanding what the expected outcome of the Mfg Lead Time Calculation should be ?
I have developed an SQL Query to scour the PartDtl table for the components and join to the PartPlant to find the Max Lead time ( for Purchased parts). If I were to put this calculated number in the Manual Top Level time, how would this effect MRP when it runs ? What other field could be used to record this lead time ? If all else fails, I could add a UD field and add it somewhere on the site Planning Page. There again I would prefer to use Epicor’s built in functions if at all possible.

Looking forward to the discussions :slight_smile:


In Site Maintenance what do you include in Mfg Lead Time Calcs?

We have Lead Time, Receive Time, Kit Time and Transfer Lead time checked ( we do not use transfers, we are 1 company)

Not sure what version you are on but the Mfg Lead Time Calc is included in the Embedded Help MRP Tech Ref Guide and the PDF MRP Tech Ref Guide, here is the Calculation per the Guide:

The Manufacturing Lead Time functionality uses this logic to calculate its results:
Purchase Part Lead Time = Number of Days to Receive Quantity
Manufacture Part Lead Time = Setup Time + Production Time
This Level Time = Total Purchase Material Time + Total Manufacturing Part Quantity Time
Cumulative Time = Subassembly 1 Time + Subassembly 2 Time + Subassembly 3 Time and so on…

My guess is you are missing the Mfg Part Lead Time


We are on 10.1.6

This is from The MRP Tech REF

The calculation considers a number of values when it determines manufacturing lead time. For each purchased
part, the calculation determines how long it takes for the part quantity to be ordered from the supplier and then
arrive at the receiving site. For each manufactured part, the calculation determines lead time by totaling the time
required at each subassembly. It first considers the number of days it will take for purchased materials to arrive
at the site. It then factors in the time it times to run setup and production on each operation. The calculation
then arrives at a total time for each subassembly. It then adds together each subassembly time to arrive at a
cumulative value for the entire part quantity.

With one of the examples I ran,

1 particular part that contains 2 purchased parts with lead times of 21 and 28 days yields a Cumulative lead time of 116 days,_

Where did the 116 days come from ??

1 Like

Probably the Setup & Production time for each of the subassemblies on the Method as well as other Part/Site specific values.
Without seeing the Method for the part you are working with, it’s hard to say.

1 Like

The 116 may be a bad example, its a Mfg Part with an outside Vendor Operation with 84 days out on the Subcontract operation. I will try to find another example for tomorrow. Thanks for the replies so far.

1 Like

That makes sense now.

I haven’t really scrutinized all Mfg Lead Times
The calculation seems pretty straightforward and the few, resulting values I checked have seemed reasonable.

1 Like

Note that the Mfg Lead Time calculation does not include any queue or move time, and, it counts Calendar days regardless of your default Production calendar. So even if your Production calendar is only M-F, the calculation will include weekends as days. If you post some screen shots, everyone may be able to better help. :slight_smile:

1 Like

I just checked a system the calculated Mfg Lead Time was only 3 days.
However, I know this normally takes 2 weeks to complete once an order is placed.

I’m guessing that build times for at least some of the lower level materials were not included.

I had similar issues when starting out with MRP/scheduling.
Depending on how methods & materials were configured for one part could mean the difference between being on the schedule for 1 or 57 days.
e.g. stock vs. non-stock, how many levels, pull-as-asm, etc…

Why it might make sense to manually enter some mfg lead times?

Yes, you sure can enter the manufacturing lead times manually. And, yes, if there is something off in your Method Of Manufacturing, it will affect the calculation. :slight_smile:

1 Like

Two things …

  1. Part > Sites > Detail is the Multi-Level CTP chk-box checked on your parts (not just the Level 0 part, all mfg-parts!)
  2. The OSP - and your supplier… don’t set as FINITE per schedule capabilities, as this constrains the outside supplier and calculations as to scheduling. EPICOR thinks only one OSP can be managed by supplier at a time! Set to INFINITE for the OSP!
1 Like

I just started digging into 1 specific part to try to unravel all the times. This part is typical of how we set up our parts. We have a top level part that calls out all purchased parts ,lets call that M1. In this M1 there are several purchased parts, P1.P2,P3. One of these purchased parts (P3), has a BOM ( materials that we maintain revisions on) but no BOO ( Operations) . The reason we do this is that we Engineer these parts for our supplier to make for us. P3 is Qty Bearing. The Parts under P3 are Not Qty Bearing( P301,P302,P303,P304). P303 and P304 also have BOM’s, parts P303-1, P030-2,P304-1 and P304-2 .

The reasoning behind the assemblies being NOT Pull as Assy or View as Assy is that the decision was made when we upgraded from Vantage 6 ( yes six !!) to E9 ( and eventually E10) that we would KanBan Receipt all of our finished goods. We are a Assembly type of Company, we do not track Machining operations, all of our resources are people. I am slowly convincing the powers that be that doing Firm Jobs has an advantage( I was hired just as we were converting from Vantage)

A picture is worth a thousand words sometimes.

One other CTP consideration in on Site configuration control (within System Setup > Company/Site Maintenance)
Modules > Invnetory management > General > Detail
lower left
Calculate lead-time-window “Part Lead time”

The Picture did not load in


CTP Planning Calculate Lead Time : Part Lead Time is Checked…

One other thing to check may be your bill of operations. If you have a particularly slow labor operation, make sure that you have enough scheduling blocks on that operation or Epicor will assume one person is working on the job (resulting in a long lead time). Also check your subcontract operations for long lead times (like found on an above post). Almost always, we have found the error on lead times attributed to one of these items. Jim

Hey Rick, Where can you update Mfg Part Lead time? I joined a company who does not utilize Epicor well. To start, I to produce a rough cut capacity outlook but entering in manufacturing lead times so start dates back date to however long the lead time is. Currently the system is having sub assembly start and finish the day before it is required. I wanted to use manufacturing lead time to back date unfirmed orders until we have the resources in place to update standards and routings. Thanks so much for your time!

Part Planning.

1 Like

James, if I understand you, you’re basically wanting the end date for the job to be farther ahead of the ship date. If this is what you mean, then I can tell you how we have resolved that problem here.

Under Part Maintenance, Sites, Planning, we have started adding 5 to receive time. We work on a 5 day production calendar. What it has done is that it has made the job suggestions put the final operation for the finished good at the Monday before the Next Monday when the parts are scheduled to ship.

When MRP Runs, it explodes this time down through all purchased parts/materials. So, if Receiving already has a 14 day lead time, it turns that purchasing suggestion into a 19 day lead. Likewise, if there is a lead time on the purchased part with an additional receive time on the purchased part, it just ads the 5 days to both of those.

It’s worked like a charm for us. No more running parts so close to ship time, leaving breathing room in case there are any issues that cause the job to be interrupted or run slow.

It’s also a great way to handle customer’s parts who have a 10 day to two week stocking requirement.

What I love most is the fact that by part number. So, if you happen to have one part that runs really slow or a press that habitually goes down, you can set that receive time at whatever interval works best for you to get that suggestion when YOU want it.

1 Like