TOOL PLANNING MODEL THE PROGRAMMING LOGIC

Chapter 5 - Developm ent o f Tool Planning System

(2) Calculates required tooling quantity based on order batch size, machining requirements and tool life (’HOW MANY OF EACH’ ?) for each component given in the production plan.

(3) Calculates the purchase order release time based on the tool required time, tool procurement lead time and loading time of parts on the shop floor (’WHEN* required ?).

(4) Aggregate the tooling requirements considering all the components in a product structure and putting them in appropriate time buckets.

This section describe how the data processing is carried out using the database files as specified in the earlier sections. A brief explanation on the programming logic of the TPS, together with its pseudo code is provided here.

There are two important routines in TPS. The first routine is called ’part tool calculations’, which computes the tooling requirements on a part by part basis (the flowchart of the process is given in Fig 5.2). The second one is called ’week’, which puts the requirements in appropriate time buckets based on planned order release date (plord_date) of components (explained with the help of a flowchart in Fig 5.3). This routine gives weekly requirements of tools, which is the final output of the TPS.

Chapter 5 - Developm ent of Tool Planning System

5.4.1 Part Tool Calculation Procedure (ALLJTOOLCAL)

It is assumed that MRP provides the parts that are to be produced in weekly time buckets. Each part has a unique part_no and is loaded on the shop floor by the planned order release date (plord_date). Each internal order is coded as order_no which represents the part_no and the order batch size of components (batch_size is dictated by the MRP). This information is stored in production plan (part_ord database).

At the start of each run, all the records in the temporary database are deleted. This is a separate routine. The data necessary to compute the requirements is retrieved from various database files (can be called as input files). These data attributes are temporarily stored in tool_req database. They are then processed further using equations [5.1] to [5.6]. These equations are given in the following pseudo code. The detailed listings in Foxpro are available from Appendix-1. The data processing logic is explained in Fig 5.2.

All the records from tool_req are transferred to all_req database after calculating the requirements for the first part (order_no). The records from tool_req are then deleted for storing the requirements for the subsequent order. However, the final output is stored in all_req database, where the data is accumulated for all parts that are listed in production plan (part_ord database). The all_req database is used as input for ’tool

Chapter 5 - Developm ent of Tool Planning System

BEGIN : PROCEDURE tool calculations USE part_ord database

DO for all parts one by one

RETRIEVE part_no, batch__size, plord_date (=reqd_date) LOCATE the process plan database for part_no

USE the selected process plan database

RETRIEVE opn_no, tool_code, machining_time

STORE opn_no, tool_code, reqd_date in tool_req database USE tool_req database

DO for all tools (tool_code) one by one RETRIEVE first tool (tool__code)

LOCATE tool_code in tool_na database Equations [5.1], [5.2], [5.3], [5.4] IF tool is returnable, THEN

Equation [5.5]

ELSE (means if non_retumable, then) Equation [5.6]

ENDIF

STORE the calculated tool required quantity in all_req database ENDDO

ENDDO END :

total jobs = unit life [5.1]

machining time no. o f tool changes = batch size

total jobs [5.2]

no. o f regrinds = estimated life

unit life [5.3]

scrap quantity - no. o f tool changes

no. o f regrinds [5.4]

total quantityreturnabU = integer (scrap quantity) + 1 [5.5]

Chapter 5 - Developm ent of Tool Planning System

^ t _ ( batch size * machining tim e\ . [5*6]

total = W (---estimated life + 1

5.4.2 Weekly Requirements Procedure (WEEK)

The part tool calculation routine stores the requirements in all_req database on the basis of orders. Each order is released by the plord_date. This date is used to put all the requirements for that part in a weekly time bucket. For each new run of TPS, there is a new weekly requirement report that is generated as part of the TPS output. How this data is utilised for planning purpose is explained in chapter 7, where different tool planning strategies were developed using simulation. The logic of this routine is explained with the following pseudo code and the flow chart (Fig 5.3).

The tool planning module was developed in the above manner using various methodologies like DFDs, the Normalisation technique and the program design. The following chapter describes how the second module, the simulation modelling system was developed and integrated with this TPS.

Chapter 5 - Developm ent of Tool Planning System

BEGIN : PROCEDURE week USE part_ord database

DO for all orders one by one (order_no)

RETRIEVE orderjio and planned order release date (plord_date) USE all_req database

SCAN for selected order_no

RETRIEVE tool_code (tcode) and required quantity (reqd_qty) USE week database

CASE 1 - IF plord_date falls in weekl, THEN STORE tool_reqd_qty in weekl CASE 2 - IF plord_date falls in week2, THEN

STORE tool_reqd_qty in week2 CASE 3 - ... CASE 4 - ... ENDSCAN ENDDO END : 92

Chapter 5 O. Develo pm en t of To o l Pla n n in g System 00 CO CO 1=

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5.1

Fig 5.2 FLOW CHART OF TOOL CALCULATION PROCEDURE / I j t a r t p r o c e d u r e ^ V A LLJO O LC A L

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