Roo Tilt Bins vs Open-Front Bins: When Each One Wins

Tilt bins and open-front bins fail in opposite directions. Here is how to choose face by face — reach depth, pick frequency, mounting height, refill route, dust exposure and ESD — using real bin dimensions rather than guesswork.

Two shapes, two different questions

A pick face usually gets specified twice. Once on the layout drawing, and once again about six months later when an operator quietly moves half the bins and nobody writes down why. The second specification is the honest one, and it is worth understanding before a bulk order goes out. Two container shapes dominate the argument at every bench, machine flank and line-side wall in an Indian plant. An open-front bin — the hopper-front shape familiar from the Supra, Hippo, Bull and Rhino families — is a fixed body with an aperture cut into the front face, so the contents stay visible and reachable while the bin itself never moves. A Roo tilt bin is a closed box carried in a frame, pivoted near its front bottom edge, shut when idle and rotated towards the picker to open.

That difference sounds cosmetic. It is not. In an open-front bin the container is static and the hand does all the travelling, so the reach depth changes continuously as stock is consumed. In a tilt bin the container does the travelling and brings its contents forward to a fixed lip, so the hand's journey is roughly the same on a full bin and on a nearly empty one. Almost everything else in this article — cycle time, mounting height, refill method, dust ingress, spillage behaviour, electrostatic behaviour, even how you write and stick your labels — follows from that single mechanical fact. Get it clear in your head and most of the specification decisions answer themselves without a meeting.

Neither shape is better in the abstract. They fail in opposite directions, which is exactly why a plant that standardises on one of them across every single face ends up with dead rows on the wall and a store cupboard full of containers nobody wanted. What follows is a method for deciding face by face rather than plant by plant, using the dimensions we can genuinely put on paper and the failure patterns that repeat across Maharashtra, Gujarat, Tamil Nadu and Karnataka. Take the reasoning first; the specific part numbers matter far less than the logic that leads you to them, and the logic transfers to whatever you already have hanging on the wall today.

What the hand actually does at each bin

Watch an operator work an open-front bin and break the motion down. The shoulder flexes, the elbow extends, the wrist sits slightly extended, and the hand enters more or less horizontally through the front aperture. Fingers go into the mass of parts, the wrist deviates sideways to scoop or pinch, and the hand withdraws along the same line. Three motions, no reset, no second hand. The variable in that sequence is the reach depth, because the parts sit wherever gravity has left them. On a full bin they are right at the mouth; on a bin at one-tenth stock they are at the back wall, and the operator is reaching into a hole with an extended shoulder and a rotated trunk.

Now watch a tilt bin. Fingers hook the front lip or the moulded grip, the forearm pulls, and the bin rotates on its pivot. As it rotates, the floor of the bin becomes a slope and the contents slide forward to the lip. The hand then enters from above rather than from in front, at a depth set by the geometry of the frame instead of by the fill level. The part is grasped and withdrawn, and then — this is the motion people forget — the bin has to be pushed shut again. Six motions instead of three, but the reach itself is shallower, more upright, and much less punishing on the shoulder over a full shift.

Whether those extra motions matter is purely a question of frequency, and this is where most specification errors begin. At twenty picks a shift, two extra motions per visit are forty motions and nobody will ever notice. At six hundred picks a shift they are twelve hundred motions, and they will show up in the cycle time study. Against that, consider what the open-front bin costs at the other end: a Panda Shelf Bin 301 has an inside length of 293 mm, so at low stock the fingertips are close to 300 mm from the front face on every single pick. That is precisely the reach operators start complaining about after three in the afternoon, and it is one of the cheapest things to fix if you are already looking at how to cut picking time with a better bin layout.

One-handed picking and the hand you forgot to count

Nearly every assembly-bench pick in practice is a one-handed pick. The other hand is holding the sub-assembly, steadying a fixture, gripping a driver, or holding a scanner. When people say a bin is easy to use, what they usually mean is that it can be worked with one hand while the other hand stays busy. An open-front bin passes that test without qualification. It is one-handed by construction, and — just as importantly — its state after the pick is identical to its state before. Nothing has to be put back, closed, latched or remembered. The bin is in the same condition for the next operator on the next shift.

A tilt bin is one-handed only under conditions. Either it holds itself open on the frame and you accept an open bin, or you close it with the same hand that just took the part, which means putting the part down or transferring it. In real plants the third option wins: the operator opens the bin at the start of the shift and leaves it open. And a tilt bin left permanently open is simply an open-front bin with an inferior mouth geometry, a worse dust angle when it matters least, and a moving joint that can now be broken. This is the most common tilt bin failure we come across, and it is a specification failure rather than an operator failure.

So the rule is a frequency rule, not a preference. If a face is worked more often than roughly once every couple of minutes through a full shift, specify open-front and solve the cleanliness problem some other way — panel position, a hinged cover over the whole bank, better extraction at the source, or a housekeeping standard. If the face is worked a handful of times a shift, which describes maintenance spares, changeover fasteners, gauge accessories, calibration shims and consumables at a tool crib, the closing motion costs you nothing measurable and buys a clean, protected part every time. Be honest about the frequency; do not use the number somebody hoped for at the design stage.

Density: positions per square metre of reachable wall

Take a real wall. A clear span of 1200 mm between two columns, 900 mm of usable height, in a machine shop near Pune. Fitted with Panda Shelf Bin 301 on 315 mm deep shelves, you get twelve bins across each shelf, because the bin measures 100 mm across the shelf. At a shelf pitch of 150 mm — enough to get a hand over a 60 mm high bin comfortably — you fit six shelves in 900 mm. That is 72 addressable positions on a wall a metre and a bit wide, holding roughly 100 litres gross between them. Swap in the transparent T versions on the top row and you can read stock levels without climbing on anything.

Now fit the same wall with a tilt bin unit sized to hold a useful quantity per position. You will get a small fraction of that count, because each bin is deeper front-to-back, taller, and needs vertical pitch for the arc as well as the body. That is not an argument against tilt bins; it is a statement that the two systems are not answering the same question. One gives you many small addresses; the other gives you fewer, larger, protected addresses. Comparing them on raw position count is meaningless. Compare them on positions you actually need at that face, which is usually a much smaller number than the wall could physically hold.

There is a second density number that matters more and gets measured less: positions reachable without the operator moving their feet. A 72-position wall where the operator has to step twice to reach the ends is really three walls, and the two outer thirds will slowly fill with slow-movers. The closed tilt bin has one genuine density advantage here — it is flush when shut, so it can sit in a 900 mm gangway in an older Kolkata or Mumbai shed where a shelf projection would be an obstruction. But when it is open, its arc can project further than the open-front shelf ever did. Decide whether that transient projection coincides with foot or MHE traffic before you commit.

Mounting height: the rules are not the same

For open-front bins the governing constraint is sight. You must be able to look down into the bin, because an open-front bin above the eye line becomes a blind hole, and blind holes produce wrong picks and silent stock-outs. For a 1650 mm operator, the top bin lip should sit around 1400 to 1450 mm. Above that, either move to transparent fronts, angle the shelf forward, or accept that the top row is bulk reserve rather than a pick face and label it accordingly. At the low end, anything below roughly 500 mm involves bending, so use sloped shelving or a tilted rail to bring the mouth towards the operator and keep the contents visible from standing height.

For tilt bins the sight constraint runs the other way, and this catches people out. When a tilt bin opens, its mouth faces upwards. Above shoulder height a tilted mouth shows you nothing at all and tips its load towards your forearm, so the top row of a tilt unit must be mounted lower than the top row of an equivalent open-front arrangement, not higher. At the bottom end the constraint is the arc: a wall-mounted tilt bin low down swings out at shin and knee level, which is a bruise, a trip hazard and a reason for someone to wedge it permanently open. A practical working band for a standing operator is roughly 800 mm to 1450 mm, with the sweet spot between 950 and 1350.

Two practical points before drilling. First, measure the arc on an actual sample against your actual wall, with the bin loaded, and mark the swept envelope on the floor with tape. Numbers on a drawing do not include the operator's knuckles or the trolley that parks there at shift change. Second, set the height for the shortest regular user, not the average one. Benches in Nashik, Rajkot and Hosur are worked by three shifts of different people, and a unit set for a 1750 mm fitter becomes a blind reach for a 1550 mm colleague. If you cannot satisfy everybody with one height, split the bank: high rows for slow-movers, the golden zone for whatever moves every day.

Refill, kanban and the captive bin problem

An open-front bin has two refill routes, and both are cheap. Either you lift the bin off its louvre panel or shelf rail, carry it to the stock point or the pallet, fill it and put it back, or you top it up in place from a transfer container. A Tote AK-421 at 400 x 255 x 100 mm outside, 365 x 230 x 90 mm inside, holds around 7.5 litres and is a sensible milk-run container for exactly this. Fill totes at the stores, wheel them to the line on a trolley, decant into the wall bins. Better still, the open-front bin can be the travelling container itself, which is what makes classic two-bin replenishment so easy to run.

A tilt bin cannot do any of that. It is captive to its frame by design; the bin does not go to the stores and come back full. Every refill is therefore an in-place pour, which means the person topping up has to hold the bin open with one hand and pour with the other, at whatever height you mounted it, from a trolley that has to be at a workable height. It also means the bin can never be the kanban signal. If your line at Chakan, Manesar or Sriperumbudur runs a two-bin pull where the empty bin is the card, tilt bins force you to bolt a separate signalling system on top — a card, a mark line, a level indicator, a route check.

That extra system is a real recurring cost, not a one-time inconvenience, because a card that goes missing is a stock-out that nobody sees coming. So the replenishment model should be part of the bin decision, and usually it is not. Tilt bins suit scheduled, checklist-driven replenishment: a store person walks a fixed route on a fixed day and tops up against a list. They suit pull-based replenishment badly. Open-front bins suit both, which is a large part of why they dominate line-side. If you already run a milk run with a printed route sheet, tilt bins cost you nothing here; if you run on empty-bin signals, count the cost of the parallel system before you compare quotations.

Dust in, parts out: the fill line nobody sets

The obvious advantage of a tilt bin is that it is shut when nobody is using it. In a deburring or off-hand grinding cell, abrasive dust settles into everything with an opening, and a Coimbatore pump shop's open-front fastener bins are visibly grey by Friday afternoon. Weld spatter, coolant mist, powder overspray and monsoon dust blowing through open shutters in Navi Mumbai all do the same. Contaminated fasteners mean damaged threads, scattered torque readings and rework that gets blamed on the tool. If a face is downwind of a dust source and the parts are threaded, sealing surfaces, or going anywhere near an assembly torque spec, the closed box is worth its extra motions.

The less obvious behaviour is that a tilt bin spills at the moment of opening, not at rest. Every open is a controlled avalanche of the contents towards the front lip. Overfill it and you get parts on the floor at every single visit, all shift, every shift. So a tilt bin needs a fill line, and almost nobody sets one. Establish it empirically: load a sample bin, swing it through its full arc, and find the level that stays inside. Mark that level with paint or tape on the first bin, photograph it, and put the photograph in the work instruction. Do not describe it in words; a line on a photo survives shift handover and a written sentence does not.

Part shape drives this more than volume does. Round parts — bearing balls, dowel pins, O-rings, ferrules, shot — cascade freely and need the most conservative fill line. Flat stampings interlock and barely move. Light plastic mouldings ride over the top of the mass and go over the lip first. Oily parts run to the lip and then drip down the outside of the frame onto the floor, which is how a clean-looking installation quietly becomes a slip hazard. Test with your worst-behaving part on a real sample before you commit to forty positions; a sample sitting on the counter at our Vashi shop for ten minutes will tell you more than a datasheet.

Vertical surfaces, and what the wall can actually take

Tilt bins earn their money where there is no floor to give. The side panel of a machine, the underside of a bench, the flank of a structural column, the inside face of a maintenance van's door, the end panel of a trolley, the wall of a narrow inspection corridor. Anywhere a shelf would project into the walking line, or where the fire officer has already told you the gangway width is not negotiable. Roo RTBW wall units exist for exactly this situation, and they beat a louvre panel with hanging open-front bins in one specific way: shut, they are a flat box, so the corridor stays a corridor for most of the day.

But the wall has to be able to take it, and this is where installations go wrong quietly. A tilt unit is a rigid frame with a moment arm. When a loaded bin swings out, the load moves forward and away from the wall, and the top fixings go into tension. That is a very different load case from a shelf, where the load sits close to the wall in compression. Older sheds in Kolkata, Howrah and the Mumbai eastern suburbs have brick infill, cement sheeting and painted-over column webs that behave badly under tension. Fix into structure, never into cladding. If the wall is doubtful, use a floor-standing stand or a post rather than gambling on a chemical anchor into a hollow block.

Louvre panels carrying open-front bins take the same class of load but with a much shorter moment arm, and — worth saying plainly — they fail quietly. A bin unclips and falls; the wall stays put. A frame pulling out of a wall takes the whole bank with it. Whichever route you take, look at what is around the installation. If the bank sits at the end of a rack run or on a column near an MHE aisle, protect the upright first with rack protectors; a stacker that has already clipped a column will clip your bin bank next, and no bin frame is designed to be a bumper. This is basic, and it is skipped on roughly half the sites we visit.

Stacking, portability and the mixed wall

Open-front bins stack, and that single property quietly does a lot of work. The Supra, Hippo, Bull and Rhino families are moulded so that bins nest into a stable column while the front mouth stays clear, which means one part number can live on a shelf, hang on a louvre panel, sit in a free-standing stack on a bench, or drop into a rack bay. When the layout changes — and it always changes — the bins move with a pair of hands and no drill. The ALKON Supra Bins family is the usual starting point for this because SB 1 through SB 8 and SB 7X give you a continuous size ladder without ever changing the mounting method.

A tilt bin does not stack, and it should not be expected to. It is a bin plus a frame, and it has exactly one home. This is not a defect; it is what you pay for a captive, closed geometry that cannot be knocked off a shelf and cannot be borrowed for a different job. But it changes the procurement question fundamentally. You stop asking how many bins and start asking how many positions, on which frame, at what pitch, on which wall. And you accept that reconfiguring next year is a drilling job with a level and a fixings list, not an afternoon of lifting things from one panel to another.

In practice the right answer at most faces is a mixed wall, and there is no shame in it. Put a tilt unit at one end for the items that are dirty, infrequent and expensive to get wrong — thread inserts, oil seals, calibration shims, precision spares, adhesive cartridges — and run a louvre panel with open-front bins directly in front of the operator for the everyday line-side items. Colour-code the two zones differently so the difference is visible from across the bay. If you want to see the size ladders side by side before deciding, our comparison of the Supra, Hippo, Bull and Rhino families lays out where each range's proportions actually differ.

Part characteristics that decide it for you

Some parts settle the argument on their own, before ergonomics or density get a vote. Rule out a tilt bin when the part is long relative to the bin — rods, shafts, long pins and extrusions will jam across the tilting mouth and either wedge the bin or come out in a shower. Rule it out for parts that interlock and must be lifted straight up rather than scooped forward, for finished or plated components that must not slide against each other, for oily items that will drip at the lip on every open, and for anything that has to be counted in place during a cycle count without being disturbed.

Rule out an open-front bin when the parts are fine enough to migrate. Small washers, shims, springs and grub screws genuinely travel between adjacent open-front bins when someone returns a handful in a hurry, and mixed fastener bins are a slow, expensive problem to unpick. Rule it out for high-value small items where casual pilferage is a real consideration, for anything directly downwind of spatter, shot blast or powder overspray, and for anything the safety team has already said must be enclosed. A closed box also settles arguments during a customer audit in a way an open bin never will.

The interesting case is the middle: small fasteners at moderate frequency, which is most of what is actually on an assembly wall. Here the instinct is to reach for tilt bins to fix the reach-depth problem, and it is usually the expensive answer. Fix it with a smaller open-front bin instead. Supra SB 1 is 125 x 100 x 60 mm outside with an inside cavity of 117 x 80 x 52 mm, so the parts are never more than about 52 mm deep and the fingers barely travel. Hippo 612/T at 100 x 110 x 53 mm outside and 80 x 90 x 43 mm inside is wider than it is deep, giving a broad, shallow mouth suited to a two-finger pick of seals or clips. Bull Bin 5, at 168 x 102 x 74 mm outside and 145 x 86 x 66 mm inside, is the step up when you need more cover at the same face. Rhino ARTB-05 at 109 x 104 x 49 mm outside, 95 x 89 x 43 mm inside, sits in similar territory with a tougher body. A shallow open-front bin removes most of the tilt bin's ergonomic advantage at a fraction of the installation effort — check that route first.

ESD zones, sliding contents and bonded frames

All the standard bin ranges are moulded in polypropylene copolymer, resin code 05, and PP is an insulator. Inside an electrostatic protected area — and there are a lot of them now across Bengaluru, Chennai, Pune and the Noida-Greater Noida belt as EMS work has grown — that matters. ALKON's ESD and conductive safe products exist for this reason, and if you are specifying into an EPA you should be asking for the specific product's resistance data to keep with your audit file rather than assuming a dark-coloured bin is a conductive one. Colour is not a property; plenty of black PP is perfectly insulative.

There is a point here specific to this comparison and it is not widely appreciated. A tilt bin has a materially higher charge-generation duty cycle than an open-front bin, because on every single opening the entire contents slide across the bin floor and against each other. Sliding dissimilar materials against one another is the textbook definition of triboelectric charging. An open-front bin's contents, by contrast, mostly sit still and get lifted out. So if tilt bins are going anywhere inside an EPA, conductive versions are not a nice-to-have, they are the only defensible specification, and the fill line discussion above becomes an ESD control as well as a housekeeping one.

The frame is the part that gets forgotten. A conductive bin sitting in an insulative frame bolted to a painted wall is a floating conductor, and in some circumstances that is worse than an ordinary insulative bin, because it can accumulate and then discharge. The frame or rail must be bonded to the EPA ground system, and the path has to be provable with a meter during the periodic audit — not assumed from the purchase order. If you cannot establish and verify that path on a machine flank or a painted column, do not put the ESD-sensitive parts there. Put them in a bonded open-front arrangement at a bench where the mat and wrist strap grounding already exists and is already being tested.

Sizing with real inside dimensions

Size by inside dimensions, always. Outside dimensions are for the shelf and the wall; inside dimensions are for the parts, and the gap between them is not trivial. Work through the ranges and the gross cavity volumes come out roughly like this: Supra SB 1 at 117 x 80 x 52 mm is about 0.49 litre; Hippo 612/T at 80 x 90 x 43 mm is about 0.31 litre; Rhino ARTB-05 at 95 x 89 x 43 mm is about 0.36 litre; Koala AKP-01 at 105 x 90 x 55 mm is about 0.52 litre; Bull Bin 5 at 145 x 86 x 66 mm is about 0.82 litre; Panda Shelf Bin 301 at 293 x 86 x 55 mm is about 1.39 litres. Tote AK-421 at 365 x 230 x 90 mm is about 7.5 litres, and a Mammoth at 740 x 250 x 290 mm inside is about 53.6 litres.

Then apply a fill factor, because gross volume is never usable volume. An open-front bin loses the wedge above the front aperture, so plan on roughly 80 per cent of gross for most part shapes. A tilt bin loses considerably more, because its fill line is set by what stays inside through the full arc — for free-flowing small parts assume something nearer 60 per cent until your own test says otherwise. The practical consequence is that a tilt bin has to be noticeably larger than the open-front bin it replaces to deliver the same days of cover. Skip this step and you will hear, three weeks after installation, that the new bins keep running dry before the milk run comes round.

Finally, sanity-check by weight, because volume alone will mislead you badly at the larger sizes. Loose steel fasteners pack at roughly 55 to 60 per cent of the space they occupy, and steel is about 7.85 g per cc. A Bull Bin 5 filled with hardware therefore lands near four kilograms — fine for a wall bin, and fine for a hand. Run the same arithmetic on a Mammoth's 53 litres and you are past two hundred kilograms, which is why bulk bins get sized by weight and only pick bins get sized by volume. Whatever you land on, confirm the working load of the frame, rail or shelf with us rather than assuming it from the bin's own capacity.

Failure modes we keep finding on Indian shop floors

Most of what goes wrong is predictable, and almost all of it is visible on a ten-minute walk. The pattern below is not exhaustive, but if you check for these on your existing installation before ordering anything new, you will usually discover that the problem you were about to solve with a purchase order is actually a mounting height or a missing fill line. Walk the wall at shift change, when the bins are at their emptiest and the operators are at their most honest, and take photographs rather than notes.

None of these are exotic. Every one of them has been sitting in plain sight on a wall somewhere for months, being walked past by people who stopped registering it long ago, which is the usual fate of a small daily irritation that nobody owns. Read the list as a survey form rather than a warning: go to the face, look for each item specifically, and write down which ones you find. The point is not to feel bad about the existing installation. The point is that four or five of these will be true at your worst face, and fixing them is nearly always cheaper and faster than replacing the bins with a different shape. Here is the list, in rough order of how often we come across each one.

Two of these deserve a line of explanation because the reasoning is not obvious. Labelling policy genuinely differs between the two bin types: an open-front bin travels for refill, so the position must be labelled as well as the bin, or a bin that goes to stores takes the identity of the location with it and you are left with an anonymous gap. A tilt bin is captive, so labelling the bin alone is sufficient and often neater. And the pivot wear issue is a placement mistake more than a product one — a tilt unit installed to protect parts from grinding dust, but mounted right beside the grinder, ingests that dust into the one moving joint in the whole arrangement. Mount it on the clean side, or upwind, and the joint lasts.

Tilt bins wedged permanently open with a cable tie, a spanner or a folded rag — the operator telling you, without words, that the pick frequency was underestimated.
Overfilled tilt bins spilling a few parts at every opening, with a small permanent scatter of hardware on the floor below that housekeeping has stopped mentioning.
Tilt units mounted so high that the operator reaches over the lip and feels around blind, which defeats the entire point of bringing the contents forward.
Pivots stiff or grinding because the unit sits directly beside the abrasive process it was bought to protect the parts from.
Open-front bins on a plain flat shelf with no front rail near a press shop or punching line, slowly walking forward under vibration until one lands on the floor.
Labels stuck on open-front bins rather than on the shelf position, so the label leaves with the bin at refill and the location becomes anonymous.
Bins bought by comparing the new range's outside dimensions against the incumbent's inside dimensions, producing a bank that holds noticeably less than the one it replaced.
Tilt bins on a mobile trolley or crash cart with no retaining catch, opening themselves over the first speed breaker in the yard.

Procurement, fitting, maintenance and a per-face checklist

Buy samples before you buy quantity, and take them to the actual face rather than the conference room. One tilt unit and two or three candidate open-front sizes from the range are enough to settle most arguments in an afternoon, and our counter at Shop-1, Gagangiri CHS, Sector 17, Vashi, Navi Mumbai is open Monday to Saturday, 10:00 to 19:00, for exactly that kind of visit — or call 93266 29967 and describe the face. Lock the colour scheme and the size ladder before you scale, because a wall assembled from three colour decisions taken six months apart looks improvised and destroys whatever colour-coding logic you started with. With 476 plus products across nine ranges there is almost always a nearer size than the one you first picked; the whole warehouse storage bins range is worth a look before you settle.

On fitting and maintenance, a short list of things that repay the effort. Mark the swept arc of a loaded tilt bin on the floor in tape before drilling a single hole. Fix into structure, never cladding. Get tilt frames genuinely level — an out-of-level tilt frame either will not stay shut or will not stay open, and both are permanent irritations. Pilot one bay for a fortnight before rolling out forty. For cleaning, PP takes soap and water happily and dislikes aggressive solvents; blow out tilt pivots at every planned maintenance, because PP against PP with grit between them is a wear pair. Respect the service range of minus 10 to plus 70 degrees Celsius: check surface temperatures with an IR gun before mounting on oven skins, near induction heaters, or on an uninsulated west-facing shed wall in Rajkot or Ahmedabad in May. Keep about five per cent spare bins of each family, and for tilt units keep spare fixings too.

Then run the checklist below per pick face, not per plant, and let it decide. If the answers split evenly, default to open-front — it is cheaper to install, cheaper to change, and it fails in ways you can see. Treat the tilt bin as the exception you justify with a specific reason: dust, enclosure, corridor width, or a surface that will not take a shelf. When you send us the enquiry, at enquiry@shreeram-metafusion.com or on 98201 01937, send a photograph of the face with a tape measure in the frame, the clear width and height, the height of the shortest regular user, the pick frequency, the worst-behaving part, and any dust or ESD constraint.

Twelve questions, one pass, five minutes at the face with a tape and a phone camera. Answer them in order and write the answers on the photograph itself, because six weeks later, when the quotation is being compared against something cheaper, the reasoning is what you will need and the reasoning is what nobody records. The last four questions in particular tend to be answered from assumption rather than observation, so go and look: stand where the operator stands, open the bin, and watch what the parts do. Everything in this article reduces to those twelve answers, and a face that scores clearly one way will keep working long after whoever specified it has moved on to another plant.

How many picks per shift at this face? Above roughly one every two minutes, open-front wins on motion count alone.
Is the second hand always occupied? If yes, and the bin will not hold itself open, tilt is impractical however clean it keeps the parts.
Does the bin need to travel — to a kit trolley, to the stores, or as the kanban signal itself? If yes, tilt is ruled out; it is captive.
What is the reach depth at ten per cent stock? If it exceeds a comfortable forearm reach, try a smaller open-front bin before you try a tilt unit.
Where is the top row's lip relative to the shortest regular user's eye line? Open-front needs to sit below it; tilt needs to sit lower still.
Is there a dust, spatter, mist or overspray source within a few metres, and is the part threaded or a sealing surface?
Is the face inside an EPA? If yes, conductive product is mandatory and the frame must be bonded and meter-verified.
Will an open bin project into a walking line, a gangway or an MHE path at any point in its arc?
Can the wall take a tension load at the top fixings, or does this need a floor-standing stand instead?
What is the honest volume needed between replenishments, measured against inside dimensions and an appropriate fill factor?
Does the part cascade, interlock, drip or ride over the top when tipped forward? Test it, do not predict it.
Who refills this face, from what container, at what height, and on what trigger?