A practical guide to BOCHU/BOCI BLT laser cutting heads: model differences + what the “options” really mean
If you’ve been shopping BOCHU (often seen as BOCI in manuals/distributor listings) BLT cutting heads, you’ve probably noticed the model names look similar BLT310, BLT421, BLT441, BLT461, BLT481 but the “feel” and feature set can be very different once you get into higher power and specialty cutting (tube/bevel).
Below is a clear, shop-floor-friendly breakdown of what changes from model to model, and what you should pay attention to when choosing options.
1) First, how BLT models are organized
Think of BLT heads as families aimed at different machine classes:
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BLT3 (e.g., BLT310): cost-effective, compact, medium/low power flat cutting head. BOCHU markets BLT310 as a “cost-effective” smart head for medium/low power work.
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BLT4 (e.g., BLT421 / BLT441 / BLT461 / BLT481 + “T” tube variants): mainstream workhorse family with stronger monitoring + options for bevel and tube cutting.
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BLT5 / BLT6: higher-power and/or more “process-intelligent” heads (more sensing, more automation support features) as shown in BOCHU’s BLT brochure feature matrix.
(This post focuses mostly on the BLT models people commonly compare when buying machines or upgrading heads BLT310 vs BLT4 models and then briefly explains how BLT5/6 fit in.)
2) BLT310: the “simple, smart, affordable” baseline
BLT310 is the one you’ll see on a lot of entry to mid-range flat-sheet machines.
Key characteristics:
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Power class: up to ≤4 kW
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Fiber interface: QBH / EOC
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Optics / zoom options (typical): spot magnification M = 1.5 / 2.0 and focus travel ±50 mm
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Cooling + gas ports: water cooling + separate cutting gas / nozzle cooling interfaces (typical BLT architecture)
What it’s “for” in real life:
If you’re cutting a lot of mild steel, stainless, aluminum in typical thickness ranges for a 1-4 kW machine, BLT310 is attractive because it’s straightforward, compact, and has the core “smart head” sensing/diagnostic concept without jumping into high-power complexity. BOCHU explicitly frames it as cost-effective for medium/low power cutting.
3) BLT4 Series: where models start to diverge (and why)
BLT4 is where the lineup becomes “choose your tier.” The model number mainly maps to power ceiling, plus some models/variants add capabilities (tube, bevel, more sensing).
The quick “what’s different” summary
From BOCHU’s BLT brochure, the BLT4 lineup is shown like this:
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BLT421: ≤8 kW
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BLT441: ≤15 kW
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BLT461: ≤20 kW
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BLT481: ≤30 kW
…and there are tube variants BLT421T and BLT441T.
BLT421 vs BLT441: the most common comparison
BLT421 (≤8 kW)
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Power: ≤8 kW
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Fiber interface (in the BLT421 manual): QBH / EOC
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Typical optical ratios listed: 100:150 / 100:200 (expressed as spot magnification M=1.5/2.0)
BLT441 (≤15 kW)
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Power: ≤15 kW
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Fiber interface (in the BLT441 manual): Q+, QD, QBH, ADD (broader compatibility for higher-power ecosystems)
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Similar zoom/focus travel concept: M=1.5/2.0 and ±50 mm focus adjustment range.
Practical takeaway:
If you’re staying in the 6–8 kW world, BLT421 is the “right-sized” head. If you’re building/selling/servicing 12–15 kW machines—or you want broader fiber-interface compatibility—the BLT441 is the natural step up.
BLT461 and BLT481: same idea, higher thermal/power headroom
BOCHU positions:
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BLT461 for ≤20 kW
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BLT481 for ≤30 kW
Even if your day-to-day cut thickness doesn’t require 20–30 kW, higher-tier heads can matter for:
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process stability at high duty cycles,
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improved survivability under harsh pierce/cut conditions,
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better matching to high-power lasers and automation throughput.
(The brochure is the clearest single place BOCHU lists these power tiers side-by-side.)
4) “Options” that matter more than the model number
When buyers say “What are the options?” with BLT heads, they usually mean a few specific choices that affect performance, consumables, and integration.
Option A: Application style — flat (plane), tube (“T”), bevel/slant
BOCHU’s BLT brochure separates BLT4 heads into:
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Plane/Slant models (flat sheet + bevel-capable setups)
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Tube cutting models labeled with “T” (e.g., BLT421T, BLT441T)
If you’re quoting a tube machine (or a combo flat+tube line), this matters because the sensor head behavior, mechanical layout, and expected motion/collision scenarios differ.
Option B: Optical configuration — 100:150 vs 100:200 (M=1.5 vs M=2.0)
In the manuals you’ll see this presented as:
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Spot magnification M=1.5/2.0 (100:150 / 100:200)
How to think about it:
This is the “focal length pairing” choice that impacts spot size, depth of focus, and how forgiving the process is across thickness ranges. You’ll typically pick based on your material mix (thin/fast vs thicker/stable) and how your process library is built.
Option C: Monitoring & protection features (the “smart head” stack)
BOCHU highlights BLT4 features like:
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Closed-loop monitoring
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Protective lens temperature monitoring
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Cutting gas pressure monitoring
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Anti-collision protection
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Pan-seal failure detection
…and more.
The key point: as you move up families (and sometimes within a family), you’re paying for a bigger “safety net” against:
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lens contamination/overheating,
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sealing failures that shorten lens life,
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unstable gas conditions that wreck cut edge quality,
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crashes that lead to expensive depot repair.
BOCHU also calls out BLT4 design themes like extensive water-cooling coverage and support for bevel cutting with an AB swing axis (machine-dependent).
Option D: Fiber interface compatibility
This is a sneaky one that can decide the whole purchase.
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BLT310: QBH / EOC
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BLT421: QBH / EOC
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BLT441: Q+, QD, QBH, ADD
If you’re retrofitting a head onto an existing laser source, or you’re standardizing a production floor, interface compatibility can save you a lot of adapter headaches (or prevent a mismatch entirely).
5) Where BLT5 and BLT6 fit (high-power + more process intelligence)
If BLT4 is “feature-complete for most shops,” BLT5/BLT6 is where BOCHU starts emphasizing more sensing/automation-like process behaviors.
From the BLT brochure:
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BLT5 series shows models like BLT520H (≤8 kW) and BLT540H (≤15 kW) plus features such as smart piercing and process monitoring listed in the matrix.
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BLT6 series shows models like BLT642H / BLT662H / BLT682H / BLT6102H with power tiers up to ≤40 kW and adds items like upper/middle/lower astigmatism detection, smart piercing, anti-explosion detection, and process monitoring in the feature table.
Practical takeaway:
If your business case involves very high power, heavy automation, or you’re trying to reduce operator babysitting during piercing/cutting, BLT6-type feature sets are aimed at that world.
6) A simple way to choose the right BLT head
Use this decision logic:
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Match the head to your laser power (with margin).
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Up to ~4 kW → BLT310 class
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Up to 8 kW → BLT421
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Up to 15 kW → BLT441
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Higher tiers → BLT461/BLT481 (per BOCHU’s matrix)
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Decide if you need tube (“T”) and/or bevel capability.
Tube variants are explicitly listed for BLT4 in BOCHU’s brochure. -
Pick optical configuration (100:150 vs 100:200) based on your material mix.
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Confirm fiber interface compatibility before you buy.