Form-based postponement in the solid hardwood supply network

Figures & data

Figure 1. The model of a solid hardwood supply network is presented with its stakeholders and the material flows between them. There is a direct flow from one entity to all entities in the next tier. The source is the forest department and the sink is the customer of either laminated wood products or for furniture sawn timber.

Figure 2. The process flow chart shows the three main production processes with lamellas (right), sawn timber (middle) and single-layer panel (left). They are connected by four decisions elements which are marked with numbers. At the left, the position of the decoupling point is presented between forecast driven and order driven. Also, the types of decisions are represented with #1 the general decision and #2, #3 and #4 the postponement decisions.

Table 1. Calculated material yields for the two different final products by considering the additional production process flows. The four decisions from the process chart are shown as well as the resulting relative material yields, which are added to the quantity of the end-product

		Lamellas for laminated timber [%]	Sawn timber for furniture products [%]
	Relative amount of input material after the drying process	64.0
#1	Chosen distribution for the raw material	60.0	40.0
#2	Standard mixed outcome
	Raw material	38.4	25.6
	By-products distribution	44.0	30.0
	By-products	16.9	7.7
	+ sawmill products	21.5	17.9
#3	Alternative utilisation of out sorted lamellas for sawn timber
	Utilisation of by-products	30.0
	+ for sawn timber	5.1
#4	Utilisation of out sorted sawn timber for single-layer panel
	Utilisation of by-products	30.0	40.0
	+ for lamellar	5.1	3.1

Table 2. The final material outputs resulting from the additional process decisions and SP are displayed. They are printed in bold for the individual SP

	Process 1		Process 2		Process 3
Sawing policy	Lamella [%]	Sawn timber [%]	Lamella [%]	Sawn timber [%]	Sorted out lamellas for furniture sawn timber [%]	Single-layer panel for the manufacture of lamellas [%]
1.1	22.0 (100%)	0.0
1.2	0.0	40.0 (100%)
2	38.4 (60%)	25.6 (40%)	21.5	17.9
3	38.4 (60%)	25.6 (40%)	21.5	17.9	23.0 (+ 5.1)
4	38.4 (60%)	25.6 (40%)	21.5	17.9	23.0 (+ 5.1)	29.7 (+ 8.2)

Table 3. Material yield and additional cost for the individual SP. For each SP, the material yields for lamellas (product 1) and sawn timber (product 2) are presented in %. From SP 1, the basis policy, the following policies are developed. There are relative cost expenditures for SP 3 and 4

Sawing policy	Material yield for product 1 and 2 [%]	Relative cost expenditures [%]
1	0.220 0.0; 0.0 0.400	0
2	0.220 0.0; 0.215 0.179; 0.0 0.400;	0
3	0.220 0.0; 0.0 0.400; 0.215 0.230;	+10
4	0.220 0.0; 0.0 0.400; 0.297 0.230;	+35

Table 4. Additional expenditures of the alternative production processes are presented depending on the sawmill production capacity in %. This results into a cost span which is shown with min and max values

Sawing policy	Sawmill capacity [m^3 of roundwood]	Cutting cost [€/m^3 roundwood]		Additional cost [€/m^3 roundwood]
1 and 2	> 45 000 (+0%)	30.00	Min	+0.00
	< 20 000 (+0%)	48.00	Max	+0.00
3	> 45 000 (+10%)	30.00	Min	+3.00
	< 20 000 (+10%)	48.00	Max	+4.80
4	> 45 000 (+35%)	30.00	Min	+10.50
	< 20 000 (+35%)	48.00	Max	+16.80

Table 5. Material performance results of the chosen SP 2, 3 and 4 as well as scenarios 1 to 5 are presented in %

	Sawing policy
Parameter	2 [%]					3 [%]					4 [%]
	S1	S2	S3	S4	S5	S1	S2	S3	S4	S5	S1	S2	S3	S4	S5
DF GLP	23	31	22	20	26	38	55	37	36	54	61	73	39	39	73
DF ST	100	100	100	100	100	96	100	100	100	100	84	100	100	100	100
A UR	68	34	29	29	34	68	34	29	29	34	68	34	27	27	34
A IR	0	8	4	4	8	0	8	4	4	8	0	9	4	4	9
A USC	44	52	46	45	51	44	52	46	45	51	44	52	43	43	52
A UFC	47	69	93	91	67	47	69	93	91	67	76	91	97	97	91

Table 6. Total cost of the chosen SP and scenarios are presented

Sawing policy	Scenarios [€]
	S1	S2	S3	S4	S5
2	306	311	313	314	309
3	304	312	318	320	317
4	292	302	313	316	310

Table 7. Here the relative-reduced costs per m³ compared to the SP values are alongside the relative additional costs

Comparison of sawing policies	$rel\mathrm{\Delta }totalcost$ [%]					$relsupcost\left[\mathrm{\%}\right]$
	S1	S2	S3	S4	S5	Min	Max
3 & 2	−0.6	0.6	1.3	2.0%	2.5	1.0	1.5
4 & 2	−4.6	−2.6	−0.2	0.8%	0.2	3.4	5.4
4 & 3	−4.0	−3.2	−1.5	−1.2%	−2.3	3.4	5.4