Stencil Department: Standard Flow - New and Existing Stencils

High Level Activities / Processing

Supply and manufacture (if needed) stencil sets for screen print processes.
Check Existing Stencil sets as fit for purpose (FFP) ahead of usage
1. Manufacture Missing member stencil(s) if needed
Wash and file screen-sets after production usage.
Manage Screen Inventory (e.g maintain levels / reclaim / order )
Recycle / Reclaim stencils
Replace split stencils
Order new screens as needed
Order required consumables: emulsions, pastes, washes etc

Inputs

From	Details
Art Dept	Stencil Set requirements on Technical Specifications
Print Department	Notification of in usage split screen(s) - Requires priority replacement
Stencil Departments	Notification of Missing / Not FFP stencils in screen set(s) that are required on forthcoming processes
Suppliers	Repaired / Re-stretched stencils

Outputs

To	Details
Print Department	Stencil Sets ready for usage
Suppliers	Screen Orders Consumables for stencils
Stencil Library	Stencil Sets for rPost-usage Filing
Suppliers	Purchase Orders for repair / re-stretch of split stencils

Current Processing Flow

Supply and manufacture (if needed) stencil sets for screen print processes.

Technical Specifications for a Screen Print Process detail the corresponding stencil set requirements.
A stencil set requirement contains the follow data attributes
1. The Design Identifier, artwork status, and description for the Art Work imagery that will be printed via the stencil set.
2. The Date the screens will be required for usage.
3. The total quantity of screens that comprise the stencil set.
4. For each member stencil within the set - its Screen Type (Size and Mesh count), and unique position identifier within the set.
5. The current State (existence and status) of both the Stencil set and each member stencil.
TOT working practices state that stencil set manufacture can occur only when the corresponding Artwork / Design has been fully signed off.
A specific search filter is used "Can Make" - that limits the records to : - un-started process lines that require stencil that don't exist where the corresponding Art work record
For those stencil requirements with signed off artwork, the stencil department will begin processing the requirements in date required (soonest) order.
Stencil Requirements typically fall into one of the following scenarios.

Scenario

Details

Stencil Set Does not exist

This applies for brand new orders - or for repeat orders where the stencil set no longer exists

Stencil Set Exists

Applies for repeat orders where the stencil set is recorded as physically existing and filed within the stencil library.

For this scenario see the checking existing stencils steps

For requirements where the stencil set does not yet exist - i.e. it requires manufacture, the following processes occur.
The stencil maker consults the detail stencil set record and prints off the position identifier labels for each member screen.
The labels contain critical information regarding the specifics of the stencil needed.
1. 1. The stencil type / mesh size needed.
  2. The position identifier for the member stencil.
  3. The design identifier of the image that the stencil set will be used to produce.
  4. The total qty of stencils that make up the set.
  5. A unique barcode which encapsulates the data.
With reference to the labels the stencil marker physically draws down equivalent blank photo sensitive emulsion "coated" stencils from the coated inventory.
The stencil maker then physically attaches the adhesive labels to the corresponding coated stencils
The stencil maker then proceeds to apply the corresponding separation image onto each coated stencil
By reference to the design identifier the stencil maker looks up the corresponding artwork separation files on the Spyder imaging workstation. The design art file has individual separations which correspond to the position identifiers denoted on the stencil labels
Thus the stencil maker is able to place the correct coated stencil into the imaging printer and select he correct separation to print onto the coated stencil
The stencil maker carries on this process until all the member stencils in the set have had their corresponding separation images applied.
The stencil set manufacture is now accounted for by denoting that the stencil set manufacture has been fully completed -this debits the pool of coated stencils and credits the pool of "in use" by the corresponding qty of Type/Mesh Size stencils
Once imaged, the stencils are physically exposed by placing in the UV exposure machine to expose and develop (make permanent) the separation image.
Once all member stencils in the set have been exposed/developed they are provided to the final checking area - a status is associated with this activity.

Check Existing Stencil sets as fit for purpose (FFP) ahead of usage

For requirements where the stencil set exists, the following process is followed
The storage location recorded as holding the stencils is visited and the stencil set removed
The stencil set is sent to pre-checking are for member set existence and FFP
Within pre-checking the stencil set Is checked to ensure all member stencils exist and are FFP
If pre-checks are passed - proceeds to final checking processes

The standard flow for manufacturing stencils is shown here

Dealing with Missing / Defective Stencils

If any member stencil is found to be defective or missing the following occurs
Staff check the existing stencil set record to establish whether the missing / defective stencils have already been administered (i.e. their status has been updated to denote they are no longer in existence)
1. 1. If they have been administered - staff proceed to step 3
  2. Staff determine whether the stencils in question are missing or defective
  3. If genuinely missing, they are accounted for by marking as reclaimed - debit of in use pool; credit of available to be coated pool
  4. For stencils that are damaged , they are accounted for by marking as split - this debits the in use pool, and credits the split pool
  5. Split stencil are then set off for repair
The (now) partial stencil set is placed and recorded as located in the part-set location
1. 1. For those member stencils that are missing, Staff print out the corresponding position identification labels, and draw down and manufacture the replacement stencils as per step 5
  2. The replacement stencils are accounted for by denoting they are now manufactured
  3. The newly manufactured stencils are then re-united with the partial set and the now whole set provided to final checking

The flow for dealing with missing stencils is shown here

Final checking

During this process any defects detected will either be remedied on the fly, or if the defect is more serious, the specific defective stencils will be reclaimed, and replacements manufactured
Once final checking is completed - the status of the screen set is updated to reflect this and the stencil set filed in accounted for storage locations ready for print production usage

Manage Screen Inventory (e.g maintain levels / reclaim / order )

Managing the Stencil Set inventory involves reviewing a dashboard which provides an high level overview and status snapshot of the stencil inventory.
In broad terms, for each type of stencil (by type, read SKU or Mesh Count and Frame Size) a series of aggregate catergorisation totals are calculated as follows

Categorisation	Business Logic
Flagged for Reclaim	An @sum quantity of the stencils by SKU that have been marked as flagged for reclaim By definition these are not regarded as In Use
Expected	An @sum quantity of the screen SKU that has been ordered but not yet been delivered. When the expected screens are received, the expected pool is debited, and the available to coat pool is credited by the quantity of the blank screen SKU booked in as received on the purchase order..
Available to coat	The quantity of this screen sku that is ready to be prepared for usage. That is, the quantity physically available to be coated with photo sensitive emulsion once prepared. Note this quantity is adjusted according to the following transactions:- It is credited when these screen SKU's flagged for reclaim are updated to reclaimed It is credited when these screen SKU's, which were expected, are booked in. It is debited when the SKU's are coated.
Coated	The quantity of the screen's SKU that are physically coated with emulsion ready for imaging. Note this quantity is adjusted according to the following transactions: It is credited when the same SKU's which are available to coat are coated. It is debited, when the SKU is in use A screen is in use when it has been:- Associated to a job order which requires stencils The screen has been created - that is, the screen's status is started.
Required	This figure is a calculated @sum of the number of screens of this size that are required on all jobs orders that have not yet begun. Specifically it is an @sum of this screen SKU where The SKU is associated to a job order The job order is not in a started status The stencil has been not been created - that is, the screen's status is not started. It is debited, when the SKU is in use A stencil is in use when it has been:- Associated to a job order which requires screens The screen has been created - that is, the screen's status is started..
Coated minus required	Indicates the number of coated screens in excess or in shortfall of current requirements. Calculated figure of [Coated - Required]
Total in Usage	Total number of the screens that have been created are associated to a job order Note this quantity is adjusted according to the following transactions: It is credited when the screen is said to be in use, meaning both the following are true:- Associated to a job order which requires screens The screen has been created, that is the screen' status is completed It is debited when the SKU is marked as reclaimed.

Managing the inventory therefore requires that following activities

Ensuring that Coated Minus Required is a positive number - i.e. an excess of stencils vs. requirements exists
If the above metric is in danger, taking remedial actions
If there are available stencils, coat them (i.e. credit coated balance)
If there as flagged for reclaim stencils - reclaim and coat them to increment the coated balance
If there are expected stencils, prioritise their receipt and process to make coated
Failing the above measure, locate existing filed stencil sets that have not been used for a period of time and reclaim and then coat these.

To assist staff in managing the inventory there are some functions that can be invoked from within the dashboard

Function

Outcome

Adjustment:

Ability to set / adjust specific categorisations without going through transaction debits/credits

Coat

Transaction based to debit available ; credit coated

Split from Coated

will debit coated ; credit split pool

Split from Available

- debit available for coating ; credit split pool

Note: The split pool is categorised only by frame size - mesh count is not longer an attribute once the physical mesh has been punctured. thus a Std 49 can when repaired become Std 62

Raise Po

Creates a purchase order email template for any screen types selected.

Notes:

To increase system performance, TOT's system does not at all times real time account for the categorisations of screen statuses.

However, there are two functions that can be run on demand. Either function can be run at a stencil type (SKU) level or across the whole inventory

Function

Comments

Calculate In use

@sum for stencil types where the following is true

Stencil has been defined as required on a Technical specification record that has been attached to a job order.

Stencil Status is not WIP or Does not exist.

Calculate Required

@sum for stencil types where the following is true

Stencil has been defined as required on a Technical specification record that has been attached to a job order.

Stencil Status is does not exist

The Job order is not in a started or completed state.

Wash and file screen-sets after production usage.

Upon completion of screen print processes, the stencil-set is returned to the screen room where the screens are physically washed to remove remnants of ink and other material encountered during the print process.
Generally speaking there are three outcomes as to what happens next. Their processing steps are summarised as below:-

Scenario	Process
Stencils no longer required (possibly one off job) -	Reclaim Stencil Set Users process the Stencil set as reclaimed Accounting:- Stencil set status updated to Not existing Member Stencil status updated to Not started Location debited In use total debited by stencil(s) Type Available to coat credited by @sum stencil(s) Type
Stencils are required for likely future usage	File Stencil Set Users process the Stencil set as Filed Accounting:- Stencil set status updated to Full Set Filed Filing Location selected and recorded Stencils physically relocated to selected storage bay Available capacity for chosen location debited by QTY of stencils
Stencils are instantly required for another job / process	Send Stencil Set to Pre-Check Users process the Stencil Set as Send to Pre-Check Accounting:- Stencil set status updated to Full Set Filed and Check over flag set Location updated from wash to Pre-Check Stencils physically relocated to Pre-Check areas

Recycle / Reclaim stencils

Stage One Identify and tagging Potentially Reclaimable stencils

Staff identify that the requirement for a stencil type(s) is in excess of corresponding @sum of (coated and uncoated) stencils
In the absence of an open purchase order which would (when delivered) cover the shortfall, staff must look to the internal inventory to cover the requirements
Staff therefore perform a find for potentially reclaimable stencil sets - this lists filed stencil sets ordered by the oldest wash date - That is, the longest duration since the set was filed
Staff constrain can then further constrain this population by the specific stencil type(s) that they require
The result of this is a list of stencil sets that contain the stencil types needed
Staff then apply a flag for reclaim tag to the records

Stage Two Reclaiming the Tagged stencil sets

Staff perform a find for stencil sets that have the flagged for reclaim tag
The record set retuned contains the location of the stencil set
The location is visited, and the stencil-set is physically drawn down
Staff then process the stencil set as Reclaimed
This causes a series of processes to occur:-
1. 1. The number of individual screens on the stencil-set record is counted.
  2. The individual member stencils are grouped by SKU / Screen Type, and a count is kept of the quantity in each grouped SKU / Screen Type..
  3. The status for each individual member stencil is set to does not exist
  4. The status for the stencil-set is set as Does Not Exist
  5. The location recorded on the stencil set is cleared, and the number of available spaces in the location record is credited by the @sum of stencils in the set
  6. In the dashboard, the following accounting entries should occur-
    1. The flagged for reclaim totals are debited by the corresponding SKU /Stencil Type group count from step 5b)
    2. The in use totals are also debited by the corresponding SKU / Screen Type group count from step 5b
    3. The available to coat totals are credited by their corresponding SKU group count from step 5b)

The flow for reclaiming stencil sets is here

Replace split stencils

Stencil splits can occur at any stage in its life cycle

The below table summarises TOT's current work practices for dealing with splits

Split Scenarios

Split stencil occurs during...	Working Practices to remedy
Stencil preparation	Splits at this stage occur when the stencil is blank - i.e. no image exposed nor attached to a job order It is either in Coated state or in an Available (non coated state) The functions split from coated or split from available are used to account for the corresponding Stencil Type The qty of splits are recorded which debit the corresponding category and credit the split pool The physical stencil is then sent for re-stretching See here for schematic
Print Run	The print run is paused The split screen is removed from the print press The stencil set detail record is opened and the corresponding stencil is processed as split (this changes the status of the stencil set to flash) Accounting wise, the in use total is debited and the split pool credit by the qty of split stencils The label for the split screen is printed out and handed to the stencil maker as a priority The process for making the stencil is outlined earlier -and is followed Once the replacement stencil is made, it is processed as complete and then out to print passed out to the print press that requires it The removed split screen is sent for repair See here for workflow schematic Note: TOT working practice is to pause a print run for a maximum of 20 mins. If the replacement stencil cannot be provided within this time frame, it is likely the print press will be reconfigured for the next job, and the print run that was paused re-started later.
Pre-Print Run	The pos identifier of the member stencil is noted This is provided to the stencil maker to draw down a coated replacement and image and make Crucially no system entries are made at this point Once the replacement stencil has been manufactured and passed back out to the print room, the split screen is accounted for by using the split from coated function in the stencil dashboard. The physical split stencil is placed in the splits ares to await repair
washing	Splits at this stage are on stencils that are in use - that is, they contain an image and are related to job order(s) The stencil set detail record is opened and the corresponding stencil is processed as split (this changes the status of the stencil set to part set Accounting wise, the in use total is debited and the split pool credit by the qty of split stencils The part set is physically file using the Put Away function The exception is where the whole stencil set is tagged to reclaim, so is processed as a reclaim See here for workflow schematic
Pre check	Splits at this stage are on stencils that are in use - that is, they contain an image and are related to job order(s) he stencil set detail record is opened and the corresponding stencil is processed as split (this changes the status of the member stencil to does not exist) The stencil set status should not update The replacement stencil will require manufacturing as outlined earlier The physical split stencil is placed in the splits ares to await repair See here for workflow schematic

Note: Currently split screens are denoted by a flashing status icon on the production layouts. Assessment needs to be made of the performance overhead for this, and alternate / more performant ways of achieving this.