Cell compatibility and changeover
What one machine can run, its parameter table states. What your line can run next Monday is the overlap of every machine standing in the row and the tooling actually sitting in your building. This page works through the distance between the two.
How a line window is formed
A machine window is a property of one machine. A line window is arithmetic. Every cell passes through every station in the row, so the format your plant can run is the overlap of the windows of the machines standing in it, and on each axis the narrowest figure in the row sets the line.
The chart is drawn from the six parameter tables in our own range. Change one model in one position and the green band moves with it.
A line of SML-C72, SML-S40 and SML-A6 reads 120 to 200 micron, because the scriber runs 120 to 220 and the stringer 110 to 200. The 110 micron figure reaches the line only where cells arrive already cut and the row starts at the stringer.
The SML-C20 takes 156 by 156 to 220 by 220 mm, wider than anything else in the range, and standing with stringers that take 166 to 210 the line reads 166 to 210. Inside that band its standard cleaving tooling covers 166 to 182 mm two-cut work.
All three stringers cover 3BB to 20BB, and the SML-S60 and the SML-S40 step to 25BB. A line built around the SML-S15 carries a ceiling of 20BB even though the stations around it would take more.
Machine by machine
Each machine constrains a different axis. Reading six separate windows rather than one range is what makes a format decision safe, and it is the difference between a line that runs your second format and a line that stops for it.
Open a card for the window as its own parameter table states it. Every figure here is a row the machine is accepted against.
Head of the line
Constrains size and thickness. Busbar count it does not constrain, because grooving and thermal cleaving work on the cell body.
Widest size window
Constrains what its cleaving tooling was made for rather than what the optics can reach.
BC stringing position
Constrains cell size, thickness, grid count, string length and cell pitch at once, including pitch below zero.
Volume stringing position
Constrains the TOPCon and PERC position at volume, and carries the lowest thickness floor in the range.
Entry stringing position
Same position at entry rated output, and the model that raises the thickness floor and caps the grid count.
Layup position
Constrains the module rather than the cell, which is why a cell change still has to be checked here.
The axis that gets misread
The thickness floor of a line is a machine difference, and it is worth saying flatly because it is regularly read as a route difference.
Nothing in that list follows from whether the line is BC or TOPCon and PERC. It follows from which model stands in which position, which is why a row carrying an SML-S15 reads a 120 micron floor and one carrying an SML-S40 with pre-cut cells reads 110.
Stringing holds breakage at 0.25 percent or better on A-grade cells, measured at 120 micron and above on the SML-S60 and the SML-S15, and at 110 micron and above on the SML-S40. So the SML-S60 runs to 110 micron, and the figure it is accepted on is stated at 120 and above. Below that the machine keeps running and breakage rises, which is a thing to know before the order rather than at acceptance.
Send the two cell formats your plant will actually run, not only the first one.
Send both formatsOne change, followed all the way
Move a stringer from one busbar count to another inside its own 3BB to 20BB window, with cell size unchanged. This is the change plants assume is a setting. It is a tooling change, specified and quoted as its own item.
Four stages, and one group of tooling that stays where it is. The diagram tracks the stage you are reading.
Busbar count is the number of ribbons landing on one cell, so the feed path, the guides that bring each ribbon to its grid line and the tooling that presses it down for infrared welding are all indexed to a grid pitch. A different grid count wants the set made for that count.
Cleaving tooling is indexed to cell size and cut count, not to busbar count, so a grid change on the stringer never reaches it. On the SML-C20 that tooling is the standard 166 to 182 mm two-cut set or a set made to your drawing. On the SML-C72 the cut is standard two-cut across its size window.
Our engineers carry out the first change as part of the installation and commissioning work that brought the machine up. Training before acceptance covers process and system parameters at the host computer, which is what a plant needs to run later changes with its own operators.
A changeover is finished when the parameter table reads correctly again, not when the tooling is bolted on. The seven rows are the rows the machine was accepted on in the first place, and they are read in order because each one sits on the one before it.
Written notice starts it, we respond inside 48 hours and put a solution back to you inside 72. Wear parts of the kind a changeover disturbs, suction cups, springs and filters, sit outside the warranty and stay in long-term supply, so a row that fails on a worn part is a part order rather than a line rebuild.
Three lines and a drawing
Tooling for a format other than the blueprint format is specified and quoted separately. Naming it while the parameter table is still being written is what keeps it a line item instead of a stoppage.
Where the free-change assumption comes from
Feeding motor sets can be switched in or out at the host computer, which is where the idea that a grid change costs nothing begins. Switching sets how many ribbons the machine feeds. It is not the whole change.
Inside the 3BB to 20BB window, moving to another busbar count still requires the matching tooling, on all three stringers.
The SML-S60 carries 20 ribbon feeding motor sets and is expandable to 25 busbars, each set switchable at the host computer. The SML-S15 carries 12 sets and is expandable to 20 grids. The SML-S40 steps to 25BB the same way, and in every case the added sets arrive with the tooling made for that grid count.
A plant reading the 3BB to 20BB line as coverage that needs nothing fitted finds at the first change that parts nobody ordered are missing, and the line waits for them.
| Model | Ribbon it is accepted on | Pull force accepted |
|---|---|---|
| SML-S60 | 0.6 mm flat | 0.5 N or better, at most one point below 0.5 N on any grid line |
| SML-S40 | 0.4 mm flat; round stock 0.29 mm flattened to 0.12 – 0.15 mm over 4.8 – 6 mm | 0.5 N or better front, 1 N or better back |
| SML-S15 | 0.7 mm flat, takes 0.6 – 1.0 mm | 0.5 N or better |
Spools on the SML-S60 run to 12 kg with a 16 or 20 mm bore, 180 mm outside diameter and 160 mm width, leaded and lead-free alike, so a ribbon change inside those limits leaves the spool station alone.
The quiet half of a changeover
The cell side of a grid change is quieter and still has to be set. Plants changing grid count and size in one step often budget only for the ribbon side.
Magazines follow a size change rather than a grid change. Positioning follows both, because it is held against a pad layout.
200
The SML-S60 holds 200 small cells. The SML-S40 works from five magazine groups, one in work, two waiting and two empty, at 300 small cells each. Both are set against the cell.
0.05 mm
7.5 °C
The SML-S60 soaks ribbon in flux before welding. The SML-S15 uses a sponge soak trough fed from a flux tank with a level gauge and low-level alarm, normally 10 litres. Welding temperature is held to 7.5 degrees with limits set at the host and an alarm outside them.
When a changeover is finished
A changeover is finished when the parameter table reads correctly again, not when the tooling is bolted on. These seven are the rows the machine was accepted on in the first place.
Everything downstream sits on positioning, which is why it is read first and the three population figures are read last.
Before shipment we run your blueprint cells and take the parameter table item by item: positioning deviation, pull force, cell pitch, breakage and continuous uptime. A machine that misses a row goes back to assembly rather than onto a truck, and you are welcome to witness it.
Size, not grid
Size changes land on the scriber differently from the way grid changes land on the stringer, and the difference is the cleaving tooling. Everything else in the machine holds across its window.
A size change is proven on the machine's own inspection before it ever reaches the stringer.
The standard set covers 166 to 182 mm two-cut work, and every other size and cut is tooled to your drawing. The rest of the machine holds across its window.
Cleaving tooling, per size and cut count
Optics, chucks, speed and breakage figure
It works from 166 by 166 to 210 by 210 mm at 120 to 220 micron with the same optical set at every size: 60 W for grooving and 300 to 500 W for thermal cleaving under a 20000 hour laser warranty. Water spray cools the groove, cleaving runs on deionised or purified water, and the downstream section dries the cell with heat.
Briefly, for completeness
Cell size
Moves the magazine and positioning tooling on the stringer and the cleaving tooling on the scriber, from the same signed drawing.
Route
A stringer model change rather than tooling on the machine you own. Station by station on our BC route page.
Thickness
What moves is the breakage condition the machine is judged against.
A format change reaches the module
A format change that reaches the string reaches the module, so the layup station is checked in the same pass. String spacing absorbs part of a change. The module outline does not.
String length moves first when cell size or cut changes, and a longer string makes a longer module.
The SML-A6 takes modules 1650 to 2500 mm long and 990 to 1450 mm wide, sets string spacing from 1 to 10 mm, and holds layup accuracy and string positioning at 0.5 mm using CCD. A format that lengthens the string lengthens the module, and the module has to stay inside those two ranges for the station to lay it up.
Window against agreement
Every machine is built and accepted against one blueprint specification that you supply and sign, however wide its window is. The signed cell drawing sets it, and the production cell and string type information reaches us within 5 to 10 working days of contract signature, so the build is set against real figures rather than a range.
Both statements are true at once. The distance between them is the tooling list.
The acceptance run is made on the blueprint cell against the blueprint table, because that is the agreement both sides signed. The second format is reached with tooling designed here from your second drawing, quoted as its own item, and proven by running it through the same seven rows once the machine is up.
A plant that wants the second format to carry acceptance figures of its own nominates it before the agreement is written, so its parameters enter the table alongside the first.
What to send
A short list of inputs, all of it already fixed by your cell supplier and module design. Formats nominated at this stage arrive with the machine. Formats nominated later arrive as a tooling order placed against a line already running, which is the same parts at a worse moment.
Pitch below zero is bought with the machine rather than fitted later, so its sign belongs on this list.
Decided at order time
Three things sit outside what a tooling change reaches, and all three are settled when the equipment list is written rather than afterwards.
We say so before the machine is specified, because none of the three can be bought back later.
01
It belongs to how the SML-S60 places and holds cells, so it comes with that machine rather than being fitted to another one later. Our BC route page sets out where that matters in an equipment list.
02
The SML-C20 suits monocrystalline and PERC cells inside its 156 to 220 mm window. Aluminium back-surface cells sit outside that window, so a plant running them scribes on a different basis.
03
The six machines on this page carry technical agreements with parameter tables to be accepted against. Other models in our range are named and shown, and the figures they can be held to are written when their agreement is.
Send your two cell drawings
Send those four for the format you start on and the format you expect to add. The machine list, the window check and the tooling items for both come back within 24 hours.
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