FANUC RoboDrill a-D21LiB

$35,000 - $70,000 (used market) Updated 2026-03-16

Key Specifications

X Travel

700 mm (27.6 in)

Y Travel

400 mm (15.7 in)

Z Travel

330 mm (13.0 in)

Spindle Taper

BT30

Table Size

850 x 410 mm (33.5 x 16.1 in)

Rapid Traverse

54 m/min (2,125 ipm)

Overview

The FANUC RoboDrill a-D21LiB is the previous-generation long-bed RoboDrill, offering 700 mm of X-axis travel for shops that needed the extended reach for longer parts or multi-part fixturing. Like the medium-bed D21MiB, the D21LiB was produced in large numbers during its production run and remains one of the most commonly available used RoboDrills on the market. For shops that need a long-bed compact VMC at used-market pricing, the D21LiB delivers the RoboDrill platform's signature speed and reliability with the added X-travel that many applications demand.

The D21LiB features X/Y/Z travels of 700 x 400 x 330 mm with a table size of 850 x 410 mm — the largest work surface in the RoboDrill family. Maximum table load is 300 kg. The BT30 spindle runs at 10,000 RPM standard with a 24,000 RPM high-speed option, and the 21-position turret ATC delivers approximately 0.8-second tool-to-tool changes. Rapid traverse is 54 m/min on all axes. The machine runs on the FANUC 31i-B control, the predecessor to today's 31i-B5.

The long-bed RoboDrill found its strongest market in production environments running side-by-side fixturing of multiple small parts on a single table. With 700 mm of X-travel, shops can fixture two or three small parts across the table and machine them in a single cycle, effectively doubling or tripling throughput compared to loading one part at a time. This approach is particularly common in automotive component production, where high volumes justify the fixture engineering investment. The longer table also accommodates parts up to approximately 650 mm in length that the medium-bed model cannot handle.

Used D21LiB machines from 2012-2017 price between $35,000 and $70,000 depending on condition, spindle hours, and options. Machines with the 24,000 RPM spindle and low hours command premium prices. The D21LiB competes in the used market against the Haas DT-2 and Brother Speedio S700X. For shops that specifically need the long-bed configuration at the lowest possible cost, the previous-generation D21LiB offers genuine RoboDrill performance at a price point that makes it accessible to smaller shops and startups.

Full Specifications

Parameter	Value
X-Axis Travel	700 mm (27.6 in)
Y-Axis Travel	400 mm (15.7 in)
Z-Axis Travel	330 mm (13.0 in)
Table Size	850 x 410 mm (33.5 x 16.1 in)
Max Table Load	300 kg (661 lb)
Spindle Speed	10,000 RPM (24,000 RPM optional)
Spindle Motor Power	11 kW (15 hp) continuous
Spindle Taper	BT30
Tool Magazine	21-position turret
Tool Change Time	0.8 sec (tool-to-tool), 1.4 sec (chip-to-chip)
Rapid Traverse Rate	54 m/min (2,125 ipm)
Positioning Accuracy	±0.004 mm (±0.00016 in)
Repeatability	±0.002 mm (±0.00008 in)
CNC Control	FANUC 31i-B
Machine Weight	4,100 kg (9,039 lb)
Floor Space Required	2,350 x 1,750 mm (92.5 x 68.9 in)

Specifications sourced from fanucamerica.com — verified 2026-03-28

Strengths & Limitations

Strengths

700 mm X-travel provides the longest reach in the RoboDrill family — essential for longer parts or multi-part side-by-side fixturing strategies
850 x 410 mm table is the largest in the RoboDrill lineup, enabling two or three small parts to be fixtured across the table for higher throughput
Excellent used-market value at $35K-$70K — long-bed RoboDrill performance at a price accessible to small shops and startups
Same 54 m/min rapids and sub-second tool changes as the medium-bed D21MiB — no speed penalty for the longer X-stroke
300 kg table load capacity is significantly higher than the short-bed models, accommodating heavier fixtures and workpieces
FANUC 31i-B control remains fully supported with parts and service, ensuring long-term operational viability

Limitations

No longer in production — available only as used machines, requiring thorough inspection of mechanical condition and spindle hours
Larger footprint than medium and short-bed RoboDrills at 2,350 x 1,750 mm — takes more floor space in tight shop layouts
Previous-generation 31i-B control lacks some features of the current 31i-B5 including enhanced high-speed processing and 5-axis functions
BT30 taper and 11 kW standard spindle limit cutting force for heavy stock removal in steel and harder materials
Tool change time of 0.8 seconds is marginally slower than the current iB5 generation's 0.7 seconds — adds up over thousands of changes per shift

Best For

Production shops running multi-part fixtures that need 700 mm of X-travel to fixture two or three small parts side-by-side for maximum throughput Shops machining parts in the 400-650 mm length range that exceed the medium-bed RoboDrill's 500 mm X-travel Budget-conscious manufacturers looking for long-bed compact VMC capability at used-market pricing without compromising on RoboDrill speed and reliability Automotive subcontractors producing medium-length precision components — valve covers, intake manifold sections, transmission housings — in high volumes Automation integrators building robotic cells who need a long-bed RoboDrill at a capital cost that allows purchasing multiple machines per cell

Frequently Asked Questions

01 How does the D21LiB compare to the current D21LiB5?

The D21LiB5 (current iB5 generation) offers the 31i-B5 control with enhanced processing, 0.7-second tool changes (vs 0.8), improved servo tuning for better surface finish, and updated thermal compensation. Mechanical dimensions and travel ranges are essentially identical. The iB5 generation provides roughly 3-5% cycle time improvement. The price difference between a used D21LiB at $35K-$70K and a new D21LiB5 at $90K-$140K is substantial.

02 What is multi-part fixturing on the long-bed RoboDrill?

Multi-part fixturing takes advantage of the 700 mm X-travel by mounting two or three identical parts side-by-side across the table. The CNC program machines all parts in sequence during a single cycle. A robot or operator loads/unloads the entire fixture set at once. This strategy effectively doubles or triples throughput compared to single-part loading, making the long-bed RoboDrill a cost-effective alternative to a pallet changer system for high-volume small-part production.

03 What should I budget for a used D21LiB?

Used D21LiB machines from 2012-2017 typically sell for $35,000-$70,000. Machines with the 24,000 RPM high-speed spindle, low spindle hours (under 15,000), and documented maintenance history command the top end. Standard 10,000 RPM spindle machines with higher hours sell at the lower end. Budget an additional $3,000-$8,000 for rigging, installation, and any immediate maintenance items identified during pre-purchase inspection.