Table 2 presents a detailed set of motions, for each technology suboperation used in the sewing process.
Table 2
Standard set of motions for taking two workpieces from one bundle with both hands for classes 50 and 80
Class 50/A07c50A; A07d50A |
No. | Left hand movement description | Symbol | TMU | Symbol | Right hand movement description |
1. | Reach for the bundle | mR45B | 14,2 | | |
2. | taking the first workpiece | G5/G2 | 5,6 | | |
3. | reach the fingers to first bundle | R4B | 3,4 | | |
4. | taking the second workpiece | G5/G2 | 5,6 | | |
5. | joint lifting of both workpieces | (M10B) | 7,9 | mR40Am | reach the workpieces |
6. | | | 0,0 | G5 | grasping by touch contact |
7. | | | 7,9 | mR20E | reach the hand along the edge |
8. | | | 2,0 | G1A | grasp both workpieces |
9. | lifting both workpieces | M10Bm | 4,3 | (M10Bm) | lift both workpieces |
10. | moving workpieces to the central work zone | mM50B | 15,4 | (mM50B) | move the workpieces to the central zone |
| ∑TMU (s) | 66,3 (2,39) |
Class 80/A07c80A; A07d80A |
No. | Left hand movement description | Symbol | TMU | Symbol | Right hand movement description |
1. | reach for the bundle | mR70B | 21,4 | | |
2. | grasp the first bundle | G5/G2 | 5,6 | | |
3. | reach the fingers to the second workpiece | R4B | 3,4 | | |
4. | grasp the second bundle | G5/G2 | 5,6 | | |
5. | joint lifting of both workpieces | (M10B) | 7,9 | mR40Am | reach for the bundle |
6. | | | 0,0 | G5 | grasping by touch contact |
8. | | | 7,9 | mR20E | reach the hand along the edge |
9. | | | 2,0 | G1A | reach for both workpieces |
10. | lift both workpiece | M10Bm | 4,3 | (M10Bm) | lift both workpieces |
11. | move the workpieces to the central work zone | mM80B | 23,7 | (mM80B) | move the workpieces to the central work zone |
| ∑TMU (s) | 81,8 (2,94) | |
The program “MTM Calculator” is designed in such a way that the combination of the defined sets of hand suboperations of the MTM system and the basic movements form work methods for each technological operation, and by applying the RAV method and the ZAK method the machine-hand time of sewing operations is determined, which by addition gives normal execution time of technological sewing operations. The final result is obtained by incorporating the fatigue coefficients, environmental factors, and the additional time coefficient into the equations used to calculate the time for the product unit, also known as the time standard (measured in TMU, hours, minutes, and seconds). In the program, various technological operations can be employed to generate a series of procedures essential for manufacturing customized clothing items.
The initial section of the program's "Main menu" is labelled as "Review and adding", and it holds significant importance as it is the primary component of the program. After choosing the "Review and adding" option, a comprehensive screen form (Fig. 2) will appear, allowing you to design the work method for technological operations and provide detailed information on fundamental movements. Within the screen form, there exists a subform called "Fr_List" where it is possible to include or remove individual movements or sets of movements for specific technological sewing operations.
Since the technological operations may consist of many motion sets and basic movements, which have to be calculated on their own in accordance with parameters such as shape and type of movement, duration of motion, etc. Command buttons for adding specific elements for motion sets, individual basic movements (which do not need to be calculated separately), eye movements, and special parameters used to calculate the time of the machine-hand suboperation of sewing straight and curved seams (calculated using formulas) are found in the column on the left side of the form. Additional data, such as the workplace designation, the technological operation name, the name of the production model to which the specified technological operation is applied, the fatigue coefficient \(({K}_{n}\)), the environmental effect coefficient \(\left({K}_{a}\right)\), and the supplementary coefficient of additional time \(\left({K}_{d}\right)\)are needed in order to design and calculate the execution time of technological operations.
Complex SQL filtering was conducted according to the partial contents of up to four characteristics (name, class, hand, and description) for an easier search and selection of an individual set of motions, as shown in Fig. 3.
It is possible to search and select individual basic movements in a similar way, Fig. 4.
When the required movement is selected, it appears in the dark grey control fields (red coloured content), the precision of the selection is confirmed, and the selection is recorded in the list of technological operations by pressing the "Entry in list" button.
Figure 5 shows a form for selecting and calculating the time required to conduct eye movements. The EF amount is fixed and equals 7.3 TMU, however the ET movement is computed using a formula and needs the actual length of the gaze shift and the distance from the eyes to be entered beforehand. The data and values for these motions can be put into the technological operation sheet by clicking the corresponding button.
Figures 6 and 7 show forms for estimating the machine-hand sewing time of a straight and curved seam using RAV and ZAK methods. The sewing time value provided by these formulas is initially in seconds, however, the numbers may be translated into TMU and placed straight into the technical worksheet.
Figure 8 shows a printed report on the contents of a single technological operation list in its basic form. It is possible to produce an expanded report that includes the movements contained in a certain set of motions. The report printout is initiated by clicking on the "Report" or "Report (movements)" buttons.
Each technological operation with advanced sets and basic motions may be archived and subsequently deleted ("Upload saved TO" button in the main menu), updated if required, and added to the list of another garment model. It is also possible to develop a whole new list or table for a technological process by clicking the "Initialize a new table" option in the main menu).
In the main menu there is also an "Edit database" button (Fig. 9), which can be used to access the editing of four key tables in the database: Motion Sets, Basic Movements, Names of Technological Operations and Names of Garment Models.
When you click the "Edit sets" button, a combined form with a subform displays. The intended elaborated set of motions is available via a combo box with a drop-down menu in the form's header. The main data of the motion set may be edited and added in the upper part of the form, while the basic movements that comprise the set can be added and edited in the sub-form.