Unternehmensberatung & Consulting International

Case studies.

Project period: October - December 2016
Bremen
Consultants involved: 2

Potenzialanalyse in der CNC-Fertigung

Aim of the REFA counselling

In the areas of CNC manufacturing and assembly at the metalworking company, optimisation potentials had to be identified. Following a holistic approach, all production processes and the material flow in manufacturing and assembly had to be examined. In particular, the productivity and coordination of the interfaces had to be analysed.

Procedure

The following measures were carried out to record the current situation:

  • Analysis of all workflows and processes
  • Process and activity analyses of the employees
  • Examination of the storage organisation and material flow
  • Valuation of the non-value-added time fractions

Results of the potential analysis

1. The CNC utilization degrees

To determine the main degrees of utilization of the machines (43 machines), Activity samplings were carried out over ten working days.

The main utilization is a planned, direct utilization of the operating means in the sense of its intended purpose (turning, milling, grinding...).

Ancillary utilization is an indirect utilization of the operating means (setup, programming...), whereby it is prepared for the main utilization, loaded, emptied or returned to its original state as planned, or whereby it is at a standstill in order to be able to check the work object within the operating means.

The activity sampling is not measured, but observed at different times. Due to the large number of Observations, a high statistical accuracy can be obtained.

The analysis identified the following weaknesses:

  • missing orders
  • missing personnel
  • Waiting times of the machines due to two-machine operation

Summary
The Utilization degrees (main utilization, setup, programming) are between 60 % and 90 % - this corresponds to the Capacity planning.
The proportion of waiting times of the machines with two-machine operation is between 7 % and 40 %.
Free machine capacities arise due to a lack of operating personnel or as a result of a lack of work orders.

2. The planning process

In sales, planning, production and purchasing, there is a pronounced departmental thinking; coordination and communication among each other must be significantly improved. For example, there is no cross-departmental planning process with scheduling. Although there is a scheduling system for the CNC machines, the transition to capacity planning is suboptimal.

3. The degree of schedule fulfilment

The schedule variances are significantly high during the observation period (cf. figures 1 and 2).

Case Study Potenzialanalyse Lieferermin Erfuellungsgrad DiagrammCase Study Potenzialanalyse Liefertermin verspaetet

4. Material management in final assembly

The assembly department has a Kardex shuttle in which pre-assembled components are stored. During the analysis, it was found that the system’s trays are not fully occupied. There is no usable order completion message from the production of the assemblies. Additions to the system are made in the warehouse on the basis of handwritten notes from the production personnel. The manual requirement determination for pre-assembled components is either carried out "by feel" or triggered when missing components are detected.

5. Material supply in final assembly

Basically, all materials are picked according to the order quantity. The central warehouse provides the work orders/materials. Small orders (small batch sizes) are concentrated and processed jointly. When the work order changes, all production workers in the individual islands prepare the materials.

6. The assembly islands

The workplaces of the assembly islands are involved in the final assembly with very different processing times, e.g. workplace 1 & 2 50 s
workplace 3 14 s
workplace 4 85 s
workplace 5 46 s
workplace 6 50 s
workplace 7 52 s
workplace 8 46 s

workplace 9 90 s
workplace 10 - 12 312 - 457 s
workplace 13 39 s
workplace 14 38 s

Due to the different processing times, work is inevitably done with buffers

7. Assembly in the central pre-assembly

For each pre-assembly, work orders are created by the warehouse and the materials are picked according to the order quantity.
The central pre-assembly is thus not controlled and supplied via a Kanban system. This also means that there is no corresponding production warehouse (supermarket) for managing the pre-assembled components.

Summary of the actual situation

On the basis of the above-described actual situation/Potential analysis, REFA Consulting has drawn up a to-do plan in close cooperation with the client, which is currently being implemented step-by-step. A cost reduction by raising the potentials in the dimension of 15 - 20 % seems achievable and realistic.

Your contact

Bettina DirksBettina Dirks
Coordination Consulting
phone +49(0)89 42 01 74 71
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