From 0402 to QFN64: What a Desktop Pick-and-Place Can Actually Handle
"What component sizes can a desktop pick-and-place actually handle?" is the question we get most often, and the honest answer is that package size is usually not the limit. The limit is tape width, nozzle choice, and how much time you're willing to spend on the small stuff.
Here's the reference chart we use, and then the four things that actually decide whether your board runs reliably.
Component Size Reference Chart
| Package | Size (mm) | Desktop Feasible? | Difficulty | Notes |
|---|---|---|---|---|
| 0402 | 1.0 × 0.5 | Yes, with care | Hard | Requires precise vacuum and slow placement speed |
| 0603 | 1.6 × 0.8 | Yes | Moderate | Good starting point for fine-pitch practice |
| 0805 | 2.0 × 1.25 | Yes | Easy | Reliable on most desktop machines |
| 1206 | 3.2 × 1.6 | Yes | Easy | Very reliable, good for beginners |
| 1210 | 3.2 × 2.5 | Yes | Easy | No issues |
| 2010 | 5.0 × 2.5 | Yes | Easy | Large passives are straightforward |
| 2512 | 6.3 × 3.2 | Yes | Easy | Power resistors, high-wattage caps |
| SOT-23 | 2.9 × 1.6 | Yes | Easy | Common for transistors, regulators |
| SOT-223 | 6.5 × 3.5 | Yes | Easy | Larger package, very reliable |
| SOT-25/SOT-26 | 2.9 × 1.6 | Yes | Easy | Multi-pin small outline |
| SOIC-8 | 4.9 × 3.9 | Yes | Easy | Standard small IC package |
| SOIC-16 | 9.9 × 3.9 | Yes | Easy | No issues |
| TSSOP-8 | 3.0 × 4.4 | Yes | Moderate | Fine pitch requires good calibration |
| TSSOP-16 | 5.0 × 4.4 | Yes | Moderate | 0.65mm pitch, manageable |
| TSSOP-20 | 6.5 × 4.4 | Yes | Moderate | Standard fine-pitch package |
| QFN-16 | 4×4 | Yes | Moderate | Exposed pad alignment is key |
| QFN-32 | 5×5 | Yes | Moderate | Common for MCUs |
| QFN-48 | 7×7 | Yes | Moderate-Hard | Fine pitch, needs precise calibration |
| QFN-64 | 9×9 | Yes | Hard | Pushing desktop limits, but doable |
| BGA-64 | 8×8 | Limited | Hard | Requires X-ray for verification |
| BGA-100+ | varies | Not recommended | - | Industrial territory |
| Connectors | varies | Yes | Easy | With proper nozzle selection |
Detailed Package Breakdown
Passive Components (0402 through 2512)
Desktop machines handle passive components well across the full size range. The challenges scale with size:
0402 is the real test. These components are 1mm × 0.5mm. At this size:
- Vacuum level matters. Too much vacuum and the component sticks to the nozzle after release. Too little and it falls off during transfer.
- Placement speed should be reduced to 50-70% of normal.
- Nozzle tip must be clean and properly sized (0.3-0.4mm inner diameter).
- A good ring light helps the vision system see the component edges.
0603 is the practical minimum for reliable production. Most desktop machines handle these without special consideration.
0805 and larger are straightforward. No special settings needed.
Small Outline Packages (SOT-23, SOT-223)
SOT packages are easy for desktop machines. The leads are large enough to see clearly, and the packages have good contrast between leads and body. Key considerations:
- SOT-23 has 3 leads at 0.95mm pitch. This is well within desktop accuracy.
- SOT-223 is larger with a thermal pad. The pad alignment is important for thermal performance but doesn't affect placement difficulty.
SOIC Packages
SOIC (Small Outline Integrated Circuit) packages are the bread and butter of desktop assembly. SOIC-8 through SOIC-20 are all straightforward:
- Lead pitch: 1.27mm (generous by modern standards)
- Package height: ~1.75mm (easy to see on camera)
- Lead width: 0.41mm (visible on most cameras)
These packages are forgiving of minor calibration errors.
TSSOP Packages
TSSOP (Thin Shrink Small Outline Package) is where desktop machines start to require more care:
- Lead pitch: 0.65mm (half of SOIC)
- Package height: ~1.1mm (thinner than SOIC)
- Lead width: 0.24mm (fine but visible)
Practical tip: TSSOP packages benefit from slower placement speed. Reduce to 70-80% of normal and ensure your vision calibration is current.
QFN Packages
QFN (Quad Flat No-leads) packages are increasingly common and are well within desktop capability:
- Key challenge: The exposed pad on the bottom must align with the PCB pad. Unlike leaded packages, there are no visible leads to verify alignment visually.
- Solution: Use the bottom camera to verify pad alignment before placement. The vision system should detect the exposed pad edges.
- Pitch range: 0.4mm to 0.65mm for the signal pads around the perimeter.
QFN-16 through QFN-48 are reliable on well-calibrated desktop machines. QFN-64 is possible but requires precise calibration and careful nozzle selection.
BGA Packages
BGA (Ball Grid Array) is where desktop machines reach their limits:
- The problem: BGA solder balls are underneath the package. You can't see them from the top camera, and the bottom camera only sees the package outline.
- Desktop feasibility: You can place BGA packages, but you cannot verify solder joint quality without X-ray inspection.
- Practical limit: BGA-64 (8×8 array, 0.8mm pitch) is the realistic maximum for desktop. Anything finer than 0.8mm pitch is industrial territory.
Recommendation: If your design requires BGA, consider using a contract manufacturer for that specific assembly step, even if the rest of the board is assembled in-house.
Connectors
Connectors vary widely in size and complexity:
- Pin headers: Easy. Large, visible pins, generous pitch.
- USB-C connectors: Moderate. Fine pitch (0.5mm) but large package size.
- FPC/FFC connectors: Moderate. Fine pitch but requires precise alignment.
- Board-to-board connectors: Easy to moderate depending on pitch.
Key insight: Connector placement is more about mechanical alignment than electrical precision. The vision system helps, but manual verification of alignment is often worthwhile for connectors that see physical stress.
Tape Width Is the Constraint You Forget About
Package size tells you nothing about how the part arrives. Everything above ships on tape, and tape width decides how much of your machine you've spent before you place a single component.
| Tape width | Typical contents |
|---|---|
| 8 mm | 0402, 0603, 0805, 1206 passives, SOT-23 |
| 12 mm | Larger passives, SOIC-8, some SOT-223 |
| 16 mm | SOIC-16, TSSOP-20, QFN-32/48 |
| 24 mm | Big QFNs, connectors, modules |
On a Vertex 4, 8 mm and 12 mm tape take one feeder slot each; 16 mm and 24 mm take two. A board with twenty 0402s and four 0603s needs two feeders — a board with one QFN-64 and three 24 mm connectors needs six slots for four parts. We've laid out the slot arithmetic in the Feeder Overview.
The other thing nobody warns you about: the same component can arrive on different tape widths from different distributors. A 10 µF cap that came on 8 mm tape last order can show up on 12 mm tape six months later, and now it doesn't fit the feeder you already loaded. Check tape width in the distributor's part data, not just the package size, and re-check it when you reorder.
What the Bottom Camera Actually Changes
A lot of the difficulty ratings above assume only a top camera. That's the wrong way to think about a machine with both.
The top camera looks down at the board and finds fiducials — that's about knowing where the board is. The bottom camera looks up at the nozzle and finds the component — that's about knowing where the part actually sits, which is not the same as where the nozzle thinks it is.
That distinction is what makes QFN placement workable without visible leads. The bottom camera sees the exposed pad's edges, and OpenPnP corrects the rotation and offset before the nozzle descends. If your QFN placement is off, the fix is almost never "try harder" — it's re-running MM/Pixel Calibration, which is what the bottom camera's accuracy depends on.
Four things decide success across every size on the chart:
- Nozzle tip matched to the component body, not the leads
- Vacuum set high enough to hold, low enough to release
- Vision calibration current — this is the one that silently degrades
- Placement speed reduced for anything under 0603
Get those four right and package size stops being the deciding factor. Get the calibration wrong and an 0805 will fail just as reliably as a 0402.
Nozzle Selection
Nozzle choice directly affects placement success across component sizes:
| Component Size | Recommended Nozzle | Inner Diameter |
|---|---|---|
| 0402 | Size 10 | 0.3mm |
| 0603-0805 | Size 15-20 | 0.4-0.5mm |
| 1206-2512 | Size 25-40 | 0.6-1.0mm |
| SOT-23 | Size 15-20 | 0.4-0.5mm |
| SOIC-8 | Size 40-50 | 1.0-1.5mm |
| QFN-32 | Size 50-60 | 1.5-2.0mm |
| QFN-64 | Size 70-80 | 2.0-2.5mm |
Rule of thumb: The nozzle tip should contact the component body, not the leads or pads. For QFN packages, center the nozzle on the exposed pad area.
Vacuum Settings
Vacuum pressure affects component handling across all sizes:
- Too high: Small components stick to the nozzle after placement. Release is unreliable.
- Too low: Components fall off during transfer from feeder to board.
- Sweet spot: Typically 60-80% of maximum vacuum for most components.
PikkoBot's vacuum system allows fine adjustment, which is critical for handling 0402 components reliably.
Placement Speed by Size
Reduce placement speed for smaller components:
| Component Size | Recommended Speed |
|---|---|
| 0402 | 50-60% |
| 0603-0805 | 70-80% |
| 1206+ | 100% |
| SOT/SOIC | 90-100% |
| TSSOP | 80-90% |
| QFN | 70-80% |
| BGA | 60-70% |
Slower placement gives the vision system more time to verify alignment and the vacuum system more time to release cleanly.
PikkoBot's Component Range
PikkoBot is rated for components from 0402 through QFN-64, with BGA placement possible (without X-ray verification). The dual-camera system and adjustable vacuum make it particularly strong for the challenging end of the spectrum: 0402 passives and fine-pitch QFN packages.
The Photon feeder system supports all standard tape sizes, from 8mm (for 0402) through 24mm (for large ICs and connectors).
If you're planning a first board, the order that saves the most time is: get homing and the fiducial right, then calibration, then practise on 0805s before you load anything under 0603.
Related Documentation
- Getting Started — first-time setup, in order
- Calibration Guide — MM/pixel and bottom camera accuracy
- Feeder Overview — tape widths, slot budget, feeder detection
- How to Choose a Feeder — matching feeders to a real BOM
- FAQ — known issues, including the ones that look like component problems and aren't