How much does it cost · manual assembly
The cost of manual assembly is the assembly time multiplied by the operator’s fully burdened hourly rate, as Bradford Range (Acorn Product Development) wrote for the DFMA Forum in June 2013. RFQdecoder counts that time operation by operation, based on the Boothroyd Dewhurst method: for example 2 to 3 s to pick up and place a small component, 8 to 12 s for a screw driven by hand. The assembly bench is costed at €30 to €50 an hour, the fully burdened rate QuoteBuddy publishes for Western European job shops (September 2026). The price of the supplied components is not counted.
RFQdecoder costs the manual assembly of a sub-assembly from supplied components. It breaks the assembly down into operations and gives each one a time based on the Boothroyd Dewhurst method (DFA, design for assembly):
Three difficulties add time to the operation concerned: difficult alignment, + 2 to 3 s; tight insertion, + 1 to 2 s; part that must be held while it is picked up, + 3 to 5 s.
When the drawing does not state a component’s size, RFQdecoder counts it as small. When it does not state how screws are driven, they are counted as driven by hand. The quote states these choices.
The total time is the sum of the operations; it is then multiplied by the hourly rate of the assembly bench.
The Boothroyd Dewhurst method splits each component into two times. Bradford Range (Acorn Product Development) sets this out in a paper presented at the 2013 International Forum on DFMA: the handling time, to prepare the part (for example picking up and positioning a screw), and the insertion time, to put it in place (for example driving the screw) (source: DFMA Forum, June 2013). He writes that assembly cost is usually estimated as the product of that time and the operator’s fully burdened labour rate (source: DFMA Forum, June 2013). In his two case studies, the times predicted by his model at sub-assembly level were within 5% of the actual times (source: DFMA Forum, June 2013).
In a DFMA Forum paper published on the Boothroyd Dewhurst website, Bill Devenish (L3Harris Technologies) states that the DFA index is based on decades of time studies by Boothroyd Dewhurst, and that the ideal assembly time for a part is 2.93 seconds (source: DFMA Forum, September 2019). His example, a circuit card screwed into a housing closed by a screwed cover, has 11 parts (source: DFMA Forum, September 2019); the analysis gives 87.64 seconds of assembly and $2.86 of labour (source: DFMA Forum, September 2019), i.e. about 8 s per part on average (calculation on this page: 87.64 ÷ 11).
FabFlow, which presents the method in a guide from July 2026, attributes the following insertion times to the Boothroyd Dewhurst classification: one-motion snap fit, 1.5 to 2.5 s; push fit or press fit, 2.0 to 3.0 s; screw into a tapped hole, 5.0 to 8.0 s; bolt and nut, 8.0 to 12.0 s; rivet set by hand, 4.0 to 6.0 s; adhesive (dispense and clamp), 8.0 to 20.0 s, cure time not included (source: FabFlow, July 2026). These are insertion times: in the method, handling the part is a separate time (source: DFMA Forum, June 2013).
For auto-fed screwdriving, Assembly Magazine states that an automated system takes about 3 seconds per screw to move to the screw point, feed the screw and drive it (source: Assembly Magazine, March 2020).
Since 4 October 2026, RFQdecoder costs assembly time at the manual assembly bench rate QuoteBuddy publishes for Western European job shops: €30 to €50 an hour, fully burdened. The rate covers the direct wage, employment costs and the bench’s share of floor space, tools and supervision (source: QuoteBuddy, September 2026).
QuoteBuddy deliberately places it below CNC machining centre rates of €60 to over €120 an hour, and writes that pricing assembly at a machine-blended rate overprices assembly-heavy work (source: QuoteBuddy, September 2026).
The same source publishes reference times for manual bench assembly in a job shop (source: QuoteBuddy, September 2026): 1.0 to 2.0 min for an electrical connection (crimp, insert, route, tie), i.e. 60 to 120 s (source: QuoteBuddy, September 2026), and 0.2 to 0.4 min for a fastener into a tapped hole with a power driver, i.e. 12 to 24 s (source: QuoteBuddy, September 2026). QuoteBuddy presents these values as starting points to check against your own timed jobs (source: QuoteBuddy, September 2026).
Assumptions chosen for illustration, not taken from a source: a bearing support assembled by hand from supplied components: a 120 mm base plate (large component), a 50 mm bearing housing (medium) that must be held while it is picked up and is fixed with 3 screws driven by hand, 2 bushes of 15 mm (small) press fitted, a 60 mm shaft (medium) with a tight insertion and a 70 mm cover (medium) snap fitted at two points.
RFQdecoder values: operation times from the list above, at the bottom and then the top of the range; assembly bench at €30 an hour at the bottom of the range and €50 an hour at the top (source: QuoteBuddy, September 2026).
Effect of quantity. This calculation counts the same time for every sub-assembly, so the cost is proportional to the quantity. For 10 sub-assemblies: 540 to 900 s, i.e. 0.15 h × €30 = €4.50 to 0.25 h × €50 = €12.50. For 100 sub-assemblies: 5,400 to 9,000 s, i.e. 1.5 h × €30 = €45.00 to 2.5 h × €50 = €125.00.
A supplier may also apply a learning curve. QuoteBuddy suggests pricing the batch average at 80 to 90% of first-unit time for 5 to 20 units, and at 70 to 80% from 50 units (source: QuoteBuddy, September 2026). Applied to this example for illustration: for 10 sub-assemblies, 540 s × 0.80 = 432 s, i.e. 0.12 h × €30 = €3.60, to 900 s × 0.90 = 810 s, i.e. 0.225 h × €50 = €11.25; for 100 sub-assemblies, 5,400 s × 0.70 = 3,780 s, i.e. 1.05 h × €30 = €31.50, to 9,000 s × 0.80 = 7,200 s, i.e. 2 h × €50 = €100.00.
The price of the components is not part of this calculation.
The price of the supplied components is not counted: RFQdecoder costs the assembly time, not the parts that make up the sub-assembly.
The operations listed above cover picking up, placing and fastening the components. QuoteBuddy describes other times that are costed separately on an assembly quote:
For adhesive bonding, the time published by FabFlow, 8.0 to 20.0 s, does not include cure time (source: FabFlow, July 2026): on a quote, check where that time is counted.
RFQdecoder counts 8 to 12 s per screw driven by hand, 3 s with an auto-feed screwdriver, and 10 to 15 s for a screw with a nut. For comparison, FabFlow attributes to the Boothroyd Dewhurst classification an insertion time of 5.0 to 8.0 s for a screw into a tapped hole (July 2026), and QuoteBuddy publishes 0.2 to 0.4 min, i.e. 12 to 24 s, for a fastener driven with a power driver in a job shop (September 2026).
QuoteBuddy publishes €30 to €50 an hour, fully burdened, for a manual assembly bench in Western European job shops (September 2026): direct wage, employment costs and the bench’s share of floor space, tools and supervision. RFQdecoder has used this rate since 4 October 2026. The same source puts CNC machining centres at €60 to over €120 an hour.
In the operation-based calculation on this page, every sub-assembly counts the same time: the example costs €0.45 to €1.25 per sub-assembly, for 10 units as for 100. A supplier may apply a learning curve: QuoteBuddy suggests pricing the average time at 80 to 90% of first-unit time for lots of 5 to 20, and at 70 to 80% from 50 (September 2026).
Components are counted as small, under 25 mm, i.e. 2 to 3 s to pick up and place, and screws are counted as driven by hand, 8 to 12 s each. The quote says so. If a component actually measures 75 to 150 mm, picking it up counts 5 to 10 s; if the screws are driven with an auto-feed screwdriver, each screw counts 3 s.
Upload your PDF, DXF or STEP drawing: routing, time and cost of each step, with every assumption shown.